Sample records for geochemical surveys

  1. The National Geochemical Survey - database and documentation (United States)

    U.S. Geological Survey, Department of the Interior — The USGS, in collaboration with other federal and state government agencies, industry, and academia, is conducting the National Geochemical Survey (NGS) to produce...

  2. The National Geochemical Survey - database and documentation (United States)

    U.S. Geological Survey, Department of the Interior — The USGS, in collaboration with other federal and state government agencies, industry, and academia, is conducting the National Geochemical Survey (NGS) to produce a...

  3. Reconnaissance soil geochemical survey of Gibraltar. (United States)

    Mesilio, Liesl; Farago, Margaret E; Thornton, Iain


    The extreme density of population of Gibraltar, situated at the southern tip of Spain, exerts considerable pressure on land use and thus future planning is of utmost importance. An initial reconnaissance soil geochemical survey of Gibraltar was based on 120 surface samples (0-15 cm) taken from a wide range of exposed, either bare soil or vegetated sites, to provide the optimum geographical distribution. The 'total' elemental concentrations of 26 elements (Li, Na, K, Be, Mg, Ca, Sr, Ba, Al, La, Ti, V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Ag, Zn, Cd, Pb, P, S, As) were determined by nitric/percholric acid digestion followed by inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis. The reconnaissance data shows that the spatial distribution of various elements depended on previous and present land use. Most elements (Ca, Cr, Mg and Mn excluded) exhibited relatively high concentrations in civilian and natural soils. Trends have been established for many elements, and concentrations exceeding guideline values have been found in certain areas of Gibraltar. This reconnaissance of Gibraltar is at present being followed by a more detailed baseline geochemical survey, which will establish the extent and magnitude of the variations in major and trace elements in soils and dusts, assess the impact of industrial, commercial and urban development on the geochemical landscape and to make recommendations concerning sustainable development.

  4. National Geochemical Survey Locations and Results for Iowa (United States)

    Iowa State University GIS Support and Research Facility — The United States Geological Survey (USGS), in collaboration with other state and federal agencies, industry, and academia, is conducting a National Geochemical...

  5. Geochemical surveys in the United States in relation to health. (United States)

    Tourtelot, H.A.


    Geochemical surveys in relation to health may be classified as having one, two or three dimensions. One-dimensional surveys examine relations between concentrations of elements such as Pb in soils and other media and burdens of the same elements in humans, at a given time. The spatial distributions of element concentrations are not investigated. The primary objective of two-dimensional surveys is to map the distributions of element concentrations, commonly according to stratified random sampling designs based on either conceptual landscape units or artificial sampling strata, but systematic sampling intervals have also been used. Political units have defined sample areas that coincide with the units used to accumulate epidemiological data. Element concentrations affected by point sources have also been mapped. Background values, location of natural or technological anomalies and the geographic scale of variation for several elements often are determined. Three-dimensional surveys result when two-dimensional surveys are repeated to detect environmental changes. -Author

  6. Review of five successful microbial geochemical surface surveys in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Munnecke, D.M. [Environmental BioTechnologies Inc., San Carlos, CA (United States)


    The development of a new surface geochemical survey technology to detect hydrocarbon microseeps was discussed. Microbial Exploration Technology (MET) was developed by Environmental BioTechnologies Inc., of San Carlos, California. It is used to determine the near surface soil`s metabolic activity towards metabolism of gaseous hydrocarbons. After several years of testing, the technology was commercialized in Canada in 1996. Since then, more than 3 million acres of land in Canada have been surveyed using MET. Surveys are conducted by collecting soil samples in a quarter by quarter mile grid pattern. The samples are then sent to California for analysis. One of the unique characteristics of MET is that it provides a contour map indicating the percent probability of drilling success. This paper presented the following five MET surveys as examples of what types of results can be obtained from the surveys: (1) Flinton Survey (T11 R6 W2), (2) Elcott Survey (T1-2 R1-3 W2), (3) Silverton Survey (T3 R32 W1), (4) Swift Current Block (T13-15 R10-R13 W3), and (5) Border Block (T1-2 R12-14 W3). Each example demonstrates that MET can be very supportive for oil and gas exploration and exploitation activities. It was suggested that running MET surveys before seismic surveys helps in determining where seismic surveys should be conducted to reduce overall exploration costs by 30 to 60 per cent, while improving drilling success. 6 figs.

  7. Geochemistry@BGS : a guide to geochemical data at the British Geological Survey


    Johnson, C C


    This report reviews the main activities in the British Geological Survey (and previously as the Institute of Geological Sciences) that have generated geochemical data. Included are; the mineral reconnaissance programme; regional geochemical mapping; groundwater geochemistry; marine and estuarine surveys; environmental geochemistry and health; radiometric surveys; isotopic geochemistry; lithogeochemical investigations; organic geochemistry laboratories; and many international activities involv...

  8. Stream sediment detailed geochemical survey for Date Creek Basin, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Butz, T.R.; Tieman, D.J.; Grimes, J.G.; Bard, C.S.; Helgerson, R.N.; Pritz, P.M.


    Results of the Date Creek Basin detailed geochemical survey are reported. Field and laboratory data are reported for 239 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are displayed. A generalized geologic map of the area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. Based on stream sediment geochemical data, significant concentrations of uranium are restricted to the Anderson Mine area. The 84th percentile concentrations of U-FL, U-NT, and U-FL/U-NT combined with low thorium/U-NT values reflect increased mobility and enrichment of uranium in the carbonate host rocks of that area. Elements characteristically associated with the uranium mineralization include lithium and arsenic. No well defined diffusion halos suggesting outliers of similar uranium mineralization were observed from the stream sediment data in other areas of the Date Creek Basin. Significant concentrations of U-FL or U-NT found outside the mine area are generally coincident with low U-FL/U-NT values and high concentrations of zirconium, titanium, and phosphorus. This suggests that the uranium is related to a resistate mineral assemblage derived from surrounding crystalline igneous and metamorphic rocks.

  9. Results of a geochemical survey, Aban Al Ahmar Quadrangle, Sheet 25F, Kingdom of Saudi Arabia (United States)

    Miller, W. Roger; Arnold, M.A.


    The interpretation of geochemical data from a regional survey of the Aban al Ahmar quadrangle resulted in the selection of areas for follow-up studies. The results of detailed geochemical studies of these areas, combined with field observation, resulted in the selection of areas of moderate to high mineral resource potential. The most important areas are (1) the Jibal Minyah area, Aban al Asmar area, Jibal Suwaj area, and Nubayah area where tin and tungsten mineralization are associated with Abanat-suite rocks or possible buried Abanat-suite plutons; (2) several areas containing rocks of the Murdama group in the northern part of the quadrangle, the Buqaya al Luaah area, and the Jabal Akkash area where precious- and base-metal mineralization are generally associated with small Idah-suite plutons; and (3) the southern periphery of Jibal Qitan associated with skarn mineralization.


    Institute of Scientific and Technical Information of China (English)


    <正>20081182 Chen Guoguang(China University of Geosciences,Wuhan 430074,China);Zhou Guohua Eco-Geochemical Assessment Based On Geosciences(Resources Survey & Environment,ISSN1671-4814,CN32-1640/N,28(2),2007,p.79-84,2 tables,6 refs.)Key words:regional geochemical


    Institute of Scientific and Technical Information of China (English)


    <正>20131784 An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China);Lei Yingping Geochemical Characteristics and Metallogenic Prospecting Areas in Yunkai Area,Guangxi(Geophysical and Geochemical Exploration,ISSN1000-8918,CN11-1906/P,36


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    <正>20110462 Chen Furong(Anhui Institute of Geological Survey,Hefei 230001,China)Ore-Search Prospects of Gold and Tungsten Geochemical Anomalies in Ningdun Area,Anhui Province(Geophysical and Geochemical Exploration,ISSN1000-8918,CN11-1906/P,34(2),2010,p.150-153,5 illus.,2 tables,6 refs.)Key words:gold ores,tungsten ores,geochemical exploration,AnhuiGeochemical anomalies of gold and tungsten in Ningdun area are dominated by the element association of Au-As-W-Bi.These anomalies are well coincident with


    Institute of Scientific and Technical Information of China (English)


    20152642 Baoyinwuliji(Inner Mongolia Institute of Geological Survey,Hohhot 010020,China);Zhao Wentao Geochemical Anomaly and Metallogenic Potential of the Naomugengsumu Lithium Mineralization Area in Inner Mongolia(Geology and Resources,ISSN1671

  14. Geological, geochemical, and geophysical survey of the geothermal resources at Hot Springs Bay Valley, Akutan Island, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Motyka, R.J.; Wescott, E.M.; Turner, D.L.; Swanson, S.E.; Romick, J.D.; Moorman, M.A.; Poreda, R.J.; Witte, W.; Petzinger, B.; Allely, R.D.


    An extensive survey was conducted of the geothermal resource potential of Hot Springs Bay Valley on Akutan Island. A topographic base map was constructed, geologic mapping, geophysical and geochemical surveys were conducted, and the thermal waters and fumarolic gases were analyzed for major and minor element species and stable isotope composition. (ACR)

  15. National Geochemical Database: Soil (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of soil samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are from the continental US...

  16. National Geochemical Database: Sediment (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of sediment samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are of stream sediment in...

  17. National Geochemical Database: Sediment (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of sediment samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are of stream sediment...

  18. Merging high resolution geophysical and geochemical surveys to reduce exploration risk at glass buttes, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Patrick [Ormat Nevada, Inc., Reno, NV (United States); Fercho, Steven [Ormat Nevada, Inc., Reno, NV (United States); Perkin, Doug [Ormat Nevada, Inc., Reno, NV (United States); Martini, Brigette [Corescan Inc., Ascot (Australia); Boshmann, Darrick [Oregon State Univ., Corvallis, OR (United States)


    The engineering and studies phase of the Glass Buttes project was aimed at reducing risk during the early stages of geothermal project development. The project’s inclusion of high resolution geophysical and geochemical surveys allowed Ormat to evaluate the value of these surveys both independently and in combination to quantify the most valuable course of action for exploration in an area where structure, permeability, and temperature are the most pressing questions. The sizes of the thermal anomalies at Glass Buttes are unusually large. Over the course of Phase I Ormat acquired high resolution LIDAR data to accurately map fault manifestations at the surface and collected detailed gravity and aeromagnetic surveys to map subsurface structural features. In addition, Ormat collected airborne hyperspectral data to assist with mapping the rock petrology and mineral alteration assemblages along Glass Buttes faults and magnetotelluric (MT) survey to try to better constrain the structures at depth. Direct and indirect identification of alteration assemblages reveal not only the geochemical character and temperature of the causative hydrothermal fluids but can also constrain areas of upflow along specific fault segments. All five datasets were merged along with subsurface lithologies and temperatures to predict the most likely locations for high permeability and hot fluids. The Glass Buttes temperature anomalies include 2 areas, totaling 60 km2 (23 mi2) of measured temperature gradients over 165° C/km (10° F/100ft). The Midnight Point temperature anomaly includes the Strat-1 well with 90°C (194 °F) at 603 m (1981 ft) with a 164 °C/km (10°F/100ft) temperature gradient at bottom hole and the GB-18 well with 71°C (160 °F) at 396 m (1300 ft) with a 182°C/km (11°F/100ft) gradient. The primary area of alteration and elevated temperature occurs near major fault intersections associated with Brothers Fault Zone and Basin and Range systems. Evidence for faulting is

  19. Interpretation of aerial gamma-ray surveys - adding the geochemical factors

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, B.L.; Scott, K.M. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience


    Aerial gamma-ray surveying reflects the geochemical variations of potassium, uranium and thorium in the upper 30 cm of the Earth`s surface. This thin layer is subject to the effects of weathering, which leads to loss of K in all rock types and, for felsic rocks, loss of U and Th as well. The extent of the loss depends on many factors, but is typically 20-30 per cent for all three radioelements. Intermediate and basic rocks show little change in radioelement concentrations during initial weathering, but pedogenesis can result in soils with 2-3 times the U and Th content of the parent rock. However, wide ranges in radioelement compositions occur for a given rock type and its weathered products. Mineralizing processes can also affect radioelement contents. For example, K is increased in altered rocks at the Copper Hill and Goonumbla porphyry Cu deposits in central NSW. Thorium concentration shows both depletion and enrichment during hydrothermal alteration, as illustrated by the Au prospects at Bimurra, in northeast Queensland. Uranium is even more erratically affected by alteration and is generally not a useful indicator of alteration. Regolith processes can affect these alteration signatures. Highly weathered deposits may lose their K, particularly if hosted by K-feldspar, as at Goonumbla. Transported soils may disguise or change rock signatures often in unexpected ways. The Mt Leyshon gold deposit, in north Queensland, is seen in the aerial survey as a K-rich area because its signature is not contaminated by material weathered from late-Silurian dolerites. Detailed interpretation of aerial gamma-ray surveys for exploration purposes requires the delineation of the major geological units of the survey area, then examination of the subtle variations within the most prospective units, aided by other data sets and field checking of the anomalous areas identified. 42 refs.,2 tabs., 13 figs.


    Institute of Scientific and Technical Information of China (English)


    20151884 An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing100083,China)Regional Geochemistry of Sanjiang Region in Yunnan Province and Its Copper-Polymetallic Prospecting Significance(Geophysical and Geochemical Exploration,ISSN1000-8918,

  1. Comparison of microbial and sorbed soil gas surgace geochemical techniques with seismic surveys from the Southern Altiplano, Bolivia

    Energy Technology Data Exchange (ETDEWEB)

    Aranibar, O.R.; Tucker, J.D.; Hiltzman, D.C.


    Yacimientos Petroliferos Fiscales Bolivianos (YPFB) undertook a large seismic evaluation in the southern Altiplano, Bolivia in 1994. As an additional layer of information, sorbed soil gas and Microbial Oil Survey Technique (MOST) geochemical surveys were conducted to evaluate the hydrocarbon microseepage potential. The Wara Sara Prospect had 387 sorbed soil gas samples, collected from one meter depth, and 539 shallow soil microbial samples, collected from 15 to 20 centimeter depth. The sorbed soil gas samples were collected every 500 meters and microbial samples every 250 meters along geochemical traverses spaced 1 km apart. The presence of anmalous hydrocarbon microseepage is indicated by (1) a single hydrocarbon source identified by gas crossplots, (2) the high gas values with a broad range, (3) the high overall gas average, (4) the clusters of elevated samples, and (5) the right hand skewed data distributions.

  2. Results of a geochemical survey, Wadi Ash Shu'Bah quadrangle, sheet 26E, Kingdom of Saudi Arabia (United States)

    Miller, W.R.; Arnold, M.A.


    The interpretation of geochemical data of a regional survey of the Wadi ash Shu'bah quadrangle resulted in the selection of areas for follow-up studies. The results of the detailed geochemical studies of these areas, combined with field observation, resulted in the identification of areas of moderate and high mineral resource potential. The most important areas are (1) the Jibal Ba'gham area for tin and tungsten resources associated with the post-Hadn Jufayfah syenogranite; (2) the Murran gossan belt, Aqab gossan area, and Rawdah gossan area for massive-sulfide mineralization associated with Hulayfah-group greenstones; (3) the Rawdat al Ba'ayith area and Jibal Abid area for precious- and base-metal mineralization associated with pre-Hadn intermediate-composition plutons; and (4) the Wadi al Qahad area for skarn and precious- and base-metal mineralization associated with pre-Hadn granodiorite.



    Liotta, Marcello; Martelli, Mauro


    Dissolved gases are often utilized in geochemical studies for investigating hydrothermal and/or magmatic contributions to shallow aquifers. Between the several methods applied for analyzing dissolved gases in water, the head space equilibration technique is probably the most used because it does not require any strain before or during the water sampling in the field and can be adapted to various aims in the laboratory, with multispecies analysis by common gas chromatography. This type of tech...

  4. Use of Multi-Media Sampling as Integrated Approach to Surficial Geochemical Sampling for Gold in Regional Reconnaissance Surveys in Parts of the Ashanti Belt, Southwest Ghana

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    Prosper M. Nude


    Full Text Available This study compared the conventional method used in surficial geochemical sampling to multimedia sampling method during reconnaissance surveys in gold exploration. The use of the conventional method in regional reconnaissance exploration surveys whereby surficial geochemical sampling is done step-wise, first by sampling stream sediments followed by rock chips then soils and other regolith materials in the search and defining of prospective targets of gold mineralization appears inefficient in geological environments characterized by complex regolith and landform modifications. However, multi-media geochemical sampling which involves the simultaneous sampling of different geochemical samples appears a better alternative and eliminates false and erratic anomalies often associated with the sampling of a single medium. Multi-media samples comprising rock chips, scree, termite mounds and lateritic lags, were collected simultaneously to support stream sediments in parts of the Ashanti belt in the Birimian of southwest Ghana, which is characterized by complex regolith and landform modifications. The most prospective targets among the three anomalous zones defined by the stream survey were better pronounced with the support of the other media, based on the consistency in significant gold contents in those samples. Gold assay values from the multi-media samples ranked the Manso East target as the most prospective and the Manso Northwest target being least prospective due to the inconsistent gold assay values in the different media. Thus the integration of the gold assay values from the various media defined real and prospective geochemical gold targets better than in the conventional method in which sampling of different media was done in stages. Unlike the conventional method, the multi-media survey provided gold results that showed regional, proximal and in-situ anomalies simultaneously. Multi-media geochemical survey therefore, appears to be a

  5. Geochemical survey of thermal system in Northeast China and their geothermometric characters

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    Mohammed Hazaea; HU Ke; Mohammed Mattash; CHEN Bing; M. O. Al-Jabali Aref; Mohammed Abdussalam


    The chemical composition of several thermal springs around Changbaishan area has been investigated.Cenozoic basaltic rocks are widely distributed in Northeast China and geothermal characteristics have been described.About one hundred hot springs exist around Changbaishan Volcano at the border between China and D.P.R.Korea with high temperature about 82℃. The pH values of the spring water range from 6.9 to 7.1 and the total flow rate is about 4.8 L /sec. The chemical composition of the thermal springs is sodium carbonate; the high-mineral contents of thermal water are believed to have medicinal properties. Bathhouses are already built along the hot springs to take the advantage of the supposed healing properties. The high quality of those hot springs is believed to be utilitized for mineral water. The chemical equilibrium temperatures were estimated at about 160℃ based on the Na-K-Ca geochemical thermometer.

  6. National Geochemical Database: Concentrate (United States)

    U.S. Geological Survey, Department of the Interior — Geochemistry of concentrates from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are from the continental US and...

  7. Geochemical soil survey of the Netherlands. Atlas of major and trace elements in topsoil and parent material; assessment of natural and anthropegenic enrichment factors

    NARCIS (Netherlands)

    Veer, G. van der


    Geochemical surveying is a generic tool to provide high quality, multi-element databases of the Earth’s surface compartments such as soil, sediment, and stream water. Such databases are not only an essential component of environmental knowledge, but also of relevance to other fields such as spatial

  8. Historical reconstruction of oil and gas spills during moderate and strong earthquakes and related geochemical surveys in Southern Apennines (United States)

    Sciarra, Alessandra; Cantucci, Barbara; Ferrari, Graziano; Pizzino, Luca; Quattrocchi, Fedora


    The aim of this study is to contribute to the assessment of natural hazards in a seismically active area of southern Italy through the joint analysis of historical sources and fluid geochemistry. In particular, our studies have been focalized in the Val d'Agri basin, in the Apennines extensional belt, since it hosts the largest oilfield in onshore Europe and normal-fault systems with high seismogenic potential (up to M7). The work was organized into three main themes: 1) literature search aimed at identifying fluid emissions during previous moderate-strong earthquakes; 2) consultation of local and national archives to identify historic local place names correlated to natural fluids emissions; 3) geochemical sampling of groundwater and gas issuing at surface, identified on the basis of the bibliographic sources. A reasoned reading of written documents and available historical data was performed. Moreover, we reworked information reported in historical catalogues, referred to liquid and gas hydrocarbon leakages occurred during seismic events of the past (in a range of magnitude from 5 to 7) in the Southern Apennines (with a particular focus on the Val d'Agri). Special attention was given to the phenomena of geochemical emissions related to major historical earthquakes that took place in the area, most notably that of 16 December 1857 (M = 7). A careful analysis of the Robert Mallet's report, a complete work aimed at describing the social impact and the effects on the environment produced by this earthquake through illustrated maps and diagrams, included several hundred monoscopic and stereoscopic photographs, was done. From archival sources (at national and/or local administrations), "sensitive" sites to the onset of leakage of liquid and gaseous hydrocarbons in the past were identified. A soil-gas survey (22 gas concentrations and flux measurements) and 35 groundwater samplings were carried out in specific sites recognized through the above studies. From a

  9. Geological and Geochemical Field Survey on the Sendai Plain following the 11 March 2011 Tohoku-Oki Tsunami (United States)

    Chague-Goff, C.; Goto, K.; Fujino, S.; Nishimura, Y.; Sugawara, D.; Szczucinski, W.; Richmond, B. M.; Tappin, D. R.; Jaffe, B. E.; Witter, R. C.; Yulianto, E.; Goff, J. R.


    A post-tsunami survey was carried out in May 2011 by members of a UNESCO-IOC International Tsunami Survey Team. The geological and geochemical survey was carried out along a transect extending 4.5 km inland north of Sendai airport, and focused on tsunami flow characteristics, sedimentation and erosion, as well as assessing the impact of saltwater contamination on the paddy fields . Tsunami inundation in this area reached c. 4.5 km inland, and the limit was marked by the elevated Tobu Highway, except where underpass structures allowed inundation further inland. The tsunami deposit generally thinned and fined inland, with the sandy deposit thinning landward from about 30 cm thickness in the coastal forest to less than 0.5 cm c. 2.8 km inland. Rip-up clasts were observed mostly near the base of the sandy deposits. Further inland, the deposit was dominated by mud, although it contained thin sand laminae one to a few grain-thick up to the limit of inundation near Tobu Highway. The thickness of the tsunami deposit was found to show large variability over short distances. Erosion and liquefaction features were also commonly observed. Ponded water was reported between the coastal forest and up to 2.6 km inland, while salt crusts were observed on numerous rice paddy fields up to the limit of tsunami inundation, where the water had evaporated. Conductivity measurements of ponded water, canals, irrigation and drainage channels revealed that the water was still saline to brackish, despite >60 mm of precipitation in the two months since the tsunami. Elevated concentrations of water-leachable chloride (salt) were measured both in mud and sand deposits, where seawater had stagnated and evaporated.

  10. Use of microwave digestion for estimation of heavy metal content of soils in a geochemical survey. (United States)

    McGrath, D


    A procedure for the rapid and safe analysis of soils with widely differing organic matter contents has been investigated and validated. Surface soils, totalling 295 and sampled on a grid basis, representing 22% of the land-base of the Republic of Ireland, have been analysed for cadmium, chromium, copper, nickel, lead and zinc. Soil concentrations of cadmium, chromium, lead and nickel exhibit patterns of regionalised elevation. Implications of this elevation are considered in relation to sewage sludge application to land, future requirement for baseline surveys and concerns over concentrations in food products.

  11. Application of Partial Content Geochemical Survey Method in Uranium Exploration%分量化探法在铀资源勘查中的应用

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    葛祥坤; 尹金双; 范光; 艾永亮; 张建锋; 金贵善; 张彦辉; 张良圣


    介绍了分量化探法勘查铀资源的理论和在我国北方砂岩型铀矿与南方热液型铀矿勘查中应用的研究成果.%The theory of partial content geochemical survey method for uranium resources prospecting was introduced and the application results in sandstone-type and hydrothermaltype uranium deposit are also discussed in this paper.

  12. Inorganic contaminants from diffuse pollution in shallow groundwater of the Campanian Plain (Southern Italy). Implications for geochemical survey. (United States)

    Cuoco, E; Darrah, T H; Buono, G; Verrengia, G; De Francesco, S; Eymold, W K; Tedesco, D


    The Campanian Plain (CP) shallow aquifer (Southern Italy) represents a natural laboratory to validate geochemical methods for differentiating diffuse anthropogenic pollution from natural water-rock interaction processes. The CP is an appropriate study area because of numerous potential anthropogenic pollution vectors including agriculture, animal husbandry, septic/drainage sewage systems, and industry. In order to evaluate the potential for geochemical methods to differentiate various contamination vectors, 538 groundwater wells from the shallow aquifer in Campanian Plain (CP) were sampled. The dataset includes both major and trace elements. Natural water-rock interactions, which primarily depend on local lithology, control the majority of geochemical parameters, including most of the major and trace elements. Using prospective statistical methods in combination with the traditional geochemical techniques, we determined the chemical variables that are enriched by anthropogenic contamination (i.e. NO3, SO4 and U) by using NO3 as the diagnostic variable for detecting polluted groundwater. Synthetic agricultural fertilizers are responsible for the majority of SO4 and U pollution throughout the CP area. Both SO4 and U are present in the groundmass of synthetic fertilizers; the uranium concentration is specifically applicable as a tracer for non-point source agricultural fertilizer contamination. The recognition of non-geological (anthropogenic) inputs of these elements has to be considered in the geochemical investigations of contaminated aquifers.


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    <正>20091835 Cheng Hangxin(School of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China);Zhuang Guangmin The Cd Geochemical Province in the Source Area of the Yangtze River and the Output Fluxes of Cd for Its Major Water Systems(Earth Science Frontiers,ISSN1005-2321,CN11-3370/P,15(5),2008,p.203-211,5 illus.,5 tables,25 refs.,with English abstract)Key words:cadmium,geochemical province,Qinghai-Tibetan Plateau20091836 Cheng Hangxin(School of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China);Yang Zhongfang A New Round of Global Geochemical

  14. Gas geochemical survey of long dormant Ciomadul volcano (South Harghita Mts., Romania): constraints on the flux and origin of fluids (United States)

    Kis, Boglárka-Mercedesz; Ionescu, Artur; Harangi, Szabolcs; Palcsu, László; Etiope, Giuseppe; Baciu, Cǎlin


    The Ciomadul, located in the South Harghita Mountains (Eastern Carpathians, Romania) is the youngest volcano built by the Neogene volcanism in the Carpathian-Pannonian Region. The volcanic activity was characterized by an initial extrusive lava dome building period from about 200 ka to 100 ka followed by a more explosive eruption stage from 57 to 32 ka. Although the volcano seems to be inactive, several features (e.g. geophysical anomalies in the crust; fast remobilization of near solidus long lasting crystal mush prior to the past eruptions) suggest that melt-bearing magmatic body could still exist beneath the Ciomadul. This is supported by the abundance of dry gas emanations (CO2, CH4, H2S), CO2 rich mineral water springs and bubbling pools. The long-term observation of seemingly inactive, dormant volcanoes has become important in the past years (Ontake volcano-Japan, Colli Albani volcano-Italy). Gas-geochemical survey and monitoring (noble gases, isotopic composition of carbon species, flux measurements) of such volcanoes is an adequate tool in detecting changes in their volcanic plumbing system. Starting from 2015 we commenced a gas-monitoring study to constrain the origin of fluids at Ciomadul by measuring the flux of two gas-species and collecting the gas-phase from several mofettes and mineral water springs. A total of 46 sites have been surveyed, including 29 gas emanations (mofettes and bubbling pools), 3 drilled wells, 11 springs and 3 surface water sites. We provide the first complex CO2 and CH4 flux measurements in the area considering mofettes and bubbling pools. The CO2 flux values range between 10 and 264 kg/day while the CH4 flux has a range between 125 and 4723 g/day. Estimates of total CO2 and CH4 output into the atmosphere are ~229 and ~1.3 t/year, respectively. These values are consistent with other geothermal systems in Europe. The chemical composition of samples indicate CO2 content of up to 96.77%, CH4 content up to 1.42% and He content up to

  15. Alaska Geochemical Database (AGDB) - Geochemical Data for Rock, Sediment, Soil, Mineral, and Concentrate Sample Media (United States)

    U.S. Geological Survey, Department of the Interior — The Alaska Geochemical Database (AGDB) was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping,...


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    <正>20122626 Li Dongfeng ( Liaoning Institute of Mineral Resources Exploration,Shenyang 110032,China ) Application of Comprehensive Geophysical-Geochemical Method in Toudao-yingzi Gold Field ( Journal of Liaoning Technical University ( Natural Sciences ), ISSN1008-0562,CN21-1379 / N,30 ( 6 ), 2011,p.849-852,1illus.,2tables,10refs. ) Key words:gold ores,geophysical exploration,geochemical exploration,Liaoning Province

  17. Geochemical reanalysis of historical U.S. Geological Survey sediment samples from the Inmachuk, Kugruk, Kiwalik, and Koyuk River drainages, Granite Mountain, and the northern Darby Mountains, Bendeleben, Candle, Kotzebue, and Solomon quadrangles, Alaska (United States)

    Werdon, Melanie B.; Granitto, Matthew; Azain, Jaime S.


    The State of Alaska’s Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska’s statewide potential for SCM resources. The SCM Assessment is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data. As part of the SCM Assessment, thousands of historical geochemical samples from DGGS, U.S. Geological Survey (USGS), and U.S. Bureau of Mines archives are being reanalyzed by DGGS using modern, quantitative, geochemical-analytical methods. The objective is to update the statewide geochemical database to more clearly identify areas in Alaska with SCM potential. The USGS is also undertaking SCM-related geologic studies in Alaska through the federally funded Alaska Critical Minerals cooperative project. DGGS and USGS share the goal of evaluating Alaska’s strategic and critical minerals potential and together created a Letter of Agreement (signed December 2012) and a supplementary Technical Assistance Agreement (#14CMTAA143458) to facilitate the two agencies’ cooperative work. Under these agreements, DGGS contracted the USGS in Denver to reanalyze historical USGS sediment samples from Alaska. For this report, DGGS funded reanalysis of 653 historical USGS sediment samples from the statewide Alaska Geochemical Database Version 2.0 (AGDB2; Granitto and others, 2013). Samples were chosen from an area covering portions of the Inmachuk, Kugruk, Kiwalik, and Koyuk river drainages, Granite Mountain, and the northern Darby Mountains, located in the Bendeleben, Candle, Kotzebue, and Solomon quadrangles of eastern Seward Peninsula, Alaska (fig. 1). The USGS was responsible for sample retrieval from the National Geochemical Sample Archive (NGSA) in Denver, Colorado through the final quality assurance/quality control (QA/QC) of the geochemical analyses obtained through the USGS contract

  18. Predicted risk of cobalt deficiency in grazing sheep from a geochemical survey; communicating uncertainty with the IPCC verbal scale. (United States)

    Lark, R. M.; Ander, E. L.; Cave, M. R.; Knights, K. V.; Glennon, M. M.; Scanlon, R. P.


    Deficiency or excess of certain trace elements in the soil causes problems for agriculture, including disorders of grazing ruminants. Farmers and their advisors in Ireland use index values for the concentration of total soil cobalt and manganese to identify where grazing sheep are at risk of cobalt deficiency. We used cokriging with topsoil data from a regional geochemical survey across six counties of Ireland to form local cokriging predictions of cobalt and manganese concentrations with an attendant distribution which reflects the joint uncertainty of these predictions. From this distribution we then computed conditional probabilities for different combinations of cobalt and manganese index values, and so for the corresponding inferred risk to sheep of cobalt deficiency and the appropriateness of different management interventions. The challenge is to communicate these results effectively to an audience comprising, inter alia, farmers, agronomists and veterinarians. Numerical probabilities are not generally well-understood by non-specialists. For this reason we presented our results as maps using a verbal scale to communicate the probability that a deficiency is indicated by local soil conditions, or that a particular intervention is indicated. In the light of recent research on the effectiveness of the verbal scale used by the Intergovernmental Panel on Climate Change to communicate probabilistic information we reported the geostatistical predictions as follows. First, we use the basic IPCC scale with intensifiers, but we also indicate the corresponding probabilities (as percentages) as recommended by Budescu et al. (2009). Second, we make it clear that the source of uncertainty in these predictions is the spatial variability of soil Co and Mn. The outcome under consideration is therefore that a particular soil management scenario would be indicated if the soil properties were known without error, possible uncertainty about the implications of particular soil

  19. Management of Reclaimed Produced Water in California Enhanced with the Expanded U.S. Geological Survey Produced Waters Geochemical Database (United States)

    Gans, K. D.; Blondes, M. S.; Kharaka, Y. K.; Reidy, M. E.; Conaway, C. H.; Thordsen, J. J.; Rowan, E. L.; Engle, M.


    In California, in 2014, every barrel of oil produced also produced 16 barrels of water. Approximately 3.2 billion barrels of water were co-produced with California oil in 2014. Half of California's produced water is generally used for steam and water injection for enhanced oil recovery. The other half (~215,000 acre-feet of water) is available for potential reuse. Concerns about the severe drought, groundwater depletion, and contamination have prompted petroleum operators and water districts to examine the recycling of produced water. Knowledge of the geochemistry of produced waters is valuable in determining the feasibility of produced water reuse. Water with low salinity can be reclaimed for use outside of the petroleum industry (e.g. irrigation, municipal uses, and industrial operations). Since a great proportion of California petroleum wells have produced water with relatively low salinity (generally 10,000-40,000 mg/L TDS), reclaiming produced water could be important as a drought mitigation strategy, especially in the parched southern San Joaquin Valley with many oil fields. The USGS Produced Waters Geochemical Database, available at, will facilitate studies on the management of produced water for reclamation in California. Expanding on the USGS 2002 database, we have more accurately located California wells. We have added new data for 300 wells in the Sacramento Valley, San Joaquin Valley and the Los Angeles Basin for a total of ~ 1100 wells in California. In addition to the existing (2002) geochemical analyses of major ions and total dissolved solids, the new data also include geochemical analyses of minor ions and stable isotopes. We have added an interactive web map application which allows the user to filter data on chosen fields (e.g. TDS management of produced waters in water-constrained California.

  20. The Source, Spatial Distribution and Risk Assessment of Heavy Metals in Soil from the Pearl River Delta Based on the National Multi-Purpose Regional Geochemical Survey. (United States)

    Zhang, Lingyan; Guo, Shuhai; Wu, Bo


    The data on the heavy metal content at different soil depths derived from a multi-purpose regional geochemical survey in the Pearl River Delta (PRD) were analyzed using ArcGIS 10.0. By comparing their spatial distributions and areas, the sources of heavy metals (Cd, Hg, As and Pb) were quantitatively identified and explored. Netted measuring points at 25 ×25 km were set over the entire PRD according to the geochemical maps. Based on the calculation data obtained from different soil depths, the concentrations of As and Cd in a large area of the PRD exceeded the National Second-class Standard. The spatial disparity of the geometric centers in the surface soil and deep soil showed that As in the surface soil mainly came from parent materials, while Cd had high consistency in different soil profiles because of deposition in the soil forming process. The migration of Cd also resulted in a considerable ecological risk to the Beijiang and Xijiang River watershed. The potential ecological risk index followed the order Cd ≥ Hg > Pb > As. According to the sources, the distribution trends and the characteristics of heavy metals in the soil from the perspective of the whole area, the Cd pollution should be repaired, especially in the upper reaches of the Xijiang and Beijiang watershed to prevent risk explosion while the pollution of Hg and Pb should be controlled in areas with intense human activity, and supervision during production should be strengthened to maintain the ecological balance of As.

  1. 地球化学勘查新技术应用研究%Application Research of the New Technologies for Geochemical Survey

    Institute of Scientific and Technical Information of China (English)

    杨少平; 弓秋丽; 文志刚; 张华; 孙忠军; 朱立新; 周国华; 成杭新; 王学求


    地球化学勘查是资源和环境领域一种十分重要的勘查评价方法技术.最近十年来地球化学勘查新方法新技术研究的重要进展主要表现在以下几个方面:①基本解决了森林沼泽区、干旱半干旱高寒山区、高寒湖沼丘陵区中普遍存在的有机质和/或风成沙对水系沉积物测量的严重干扰问题,确定采样粒级为:森林沼泽区和高寒湖沼丘陵区-10~+60目,干旱半干旱高寒山区-10~+40目或-10~+80目.大大改善了这些地区的地质找矿效果,新找到了以沱沱河多金属矿田为代表的一批有影响的大型一超大型矿床,开创了资源勘查的新局面.②建立了覆盖区多目标区域地球化学调查方法技术体系:以1点/4 km2系统采集地表(20 cm以内)和以1点/16 km2系统采集1.5m深度土壤样品,测试54种元素和指标.提出了农业、环境和城市地球化学异常查证及评价方法.为建立绿色和特色农牧产品基地、碳循环研究提供出高质量的基础地球化学资料.完成了中国勘查地球化学向环境调查领域的成功转型.③深穿透地球化学理论和方法技术研究获得了一定的进展,发现了纳米尺度金属微粒从深部向地表迁移的线索,初步制定出深穿透地球化学样品的特殊分析测试方法技术.④油气化探方法技术在曲折中发展前进,初步建立起了完整的勘查方法技术体系,在油气勘查工作中得到一定程度的推广应用,取得了一些成功的油气勘查案例.%Geochemical survey is one of the most important exploration and evaluation methods in resources and environment field. Some new progresses made in research of new methods of geochemical exploration during past ten years are summarized in following aspects. Dthe disturbances of organic material and/or eolian sands over stream sediment survey in forest-swamp, arid or semi-arid high-cold mountain, and high-cold lake-swamp hilly land were preliminarily

  2. The Survey of hydro-geochemical and health related of water quality in Ramian city, Golestan province

    Directory of Open Access Journals (Sweden)

    fahimeh Khanduzi


    Full Text Available Background and Purpose: Investigation of water quality is an important step for the suitable use of water resources in order to drinking and irrigation. Water quality affects agriculture programming.  Hence the need of the study of water quality is strongly considered in the water resources management. Material and Methods: In this study Hydro-geochemical quality of ground water resources in the Ramian city -Golestan province has been studied for drinking and agriculture purpose. For this purpose, 15 qualitative characteristics of the 13 wells of Golestan province in two dry and wet seasons in 2011-2012 were analyzed by Aua Chem and Aq-qa. Results: The results showed that the ground water in the study area is classified in hard and very hard water. The original cations and anions in water are Ca2+> Mg2+> Na+ and HCO3-> Cl-> SO42-. Based on hydro-chemical diagram the dominant of water type is classified as Ca-HCO3. Salinity index of water indicated that more samples in two seasons are in the middle class. According to Schuler and Wilcox groundwater quality index, they are moderate suitable for agricultural and drinking consumption and in for agricultural purpose and 77% cases are in C3-S1 category. Conclusion: The results show that too much salt is one of the most important problems of water supply in the Ramian city for irrigation. This reduced plant growth or even stops the growth of some plant. If water resources in this area do not manage, after shortly time the soil will be suffered and polluted.

  3. Geochemical survey of medium temperature geothermal resources from the Baja California Peninsula and Sonora, México (United States)

    Barragán R, R. M.; Birkle, P.; Portugal M, E.; Arellano G, V. M.; Alvarez R, J.


    Waters from hot springs and deep wells from Cerritos in the northern Baja California Peninsula and deep wells from the Riı´to zone (Sonora state) were studied in order to classify medium temperature geothermal resources to be exploited in NW-Mexico. Geochemical characteristics of San Felipe and Punta Estrella coastal springs indicate the mixing of seawater and meteoric components with secondary leaching of evaporates. Reservoir temperatures for both zones were estimated up to 225°C. Mixing of high portions of seawater (>80 wt%) with local waters could be the origin for the Puertecitos coastal spring, with a reservoir temperature estimation of 195°C. The El Coloradito coastal spring is composed of meteoric water with a reservoir temperature of 127°C. The formation of thermal manifestations along the Baja California coast could be related to the heating up of convecting seawater along extensional tectonic structures, as observed for submarine hydrothermal vents at the Gulf of California and along the East Pacific Rise. Volcanic steam-heated waters with a reservoir temperature of 135°C were found at the Valle Chico inland springs from the Baja California Peninsula. Deep fluids from the Riı´to zone originated by evaporation of infiltrated waters with similar characteristics to those located in the Mexicali Valley. Reservoir temperature of 192 and 126°C are estimated for the Riı´to deep wells ER-1B (ER) and R-1, respectively. The Riı´to artesian wells M-1, M-2 and M-4 indicate reservoir temperatures from 109 to 118°C. Isotopic data define the artesian wells as typical surface water or shallow groundwater from the Mexicali Valley. The Cerritos deep fluids of the Mexicali Valley show a close chemical and isotopic relationship to the adjacent Cerro Prieto reservoir fluids suggesting a similar origin and a possible connection of both aquifer systems. Conductive cooling of Cerro Prieto discharge fluids could originate the cooler Cerritos system (130


    Institute of Scientific and Technical Information of China (English)


    <正>20111167 Cao Zhonghuang(Wuhan Iron & Steel Group Minerals Company,Wuhan 430063,China);Luo Xianrong Comparative Study of Copper-Nickel Deposit Exploration by the Geoelectro-chemical Extraction Method in Different Overburden Areas(Geology and Prospecting,ISSN0495-5331,CN11-2043/P,46(3),2010,p.476-482,4 illus.,5 tables,20 refs.)Key words:geo-electrochemical methods,copper ores,nickel ores,Gansu Province,Jilin Province The authors have made a comparative study of quantitative and qualitative analysis and application of the geoelectro-chemical extraction method in different overburden areas in southward extension of Jinchuan in Gansu Province and Hongqiling in Jilin Province.The authors found that this method extracted very few ions in arid areas covered with debris,but the prospecting effect was almost the same as that in moist areas covered with thick overburden.And this method could show objectively differences of geochemical characters

  5. Blind Geothermal System Exploration in Active Volcanic Environments; Multi-phase Geophysical and Geochemical Surveys in Overt and Subtle Volcanic Systems, Hawai’i and Maui

    Energy Technology Data Exchange (ETDEWEB)

    Fercho, Steven [Ormat Nevada, Inc., Reno, NV (United States); Owens, Lara [Ormat Nevada, Inc., Reno, NV (United States); Walsh, Patrick [Ormat Nevada, Inc., Reno, NV (United States); Drakos, Peter [Ormat Nevada, Inc., Reno, NV (United States); Martini, Brigette [Corescan Inc., Ascot (Australia); Lewicki, Jennifer L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kennedy, Burton M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)


    Suites of new geophysical and geochemical exploration surveys were conducted to provide evidence for geothermal resource at the Haleakala Southwest Rift Zone (HSWRZ) on Maui Island, Hawai’i. Ground-based gravity (~400 stations) coupled with heli-bourne magnetics (~1500 line kilometers) define both deep and shallow fractures/faults, while also delineating potentially widespread subsurface hydrothermal alteration on the lower flanks (below approximately 1800 feet a.s.l.). Multi-level, upward continuation calculations and 2-D gravity and magnetic modeling provide information on source depths, but lack of lithologic information leaves ambiguity in the estimates. Additionally, several well-defined gravity lows (possibly vent zones) lie coincident with magnetic highs suggesting the presence of dike intrusions at depth which may represent a potentially young source of heat. Soil CO2 fluxes were measured along transects across geophysically-defined faults and fractures as well as young cinder cones along the HSWRZ. This survey generally did not detect CO2 levels above background, with the exception of a weak anomalous flux signal over one young cinder cone. The general lack of observed CO2 flux signals on the HSWRZ is likely due to a combination of lower magmatic CO2 fluxes and relatively high biogenic surface CO2 fluxes which mix with the magmatic signal. Similar surveys at the Puna geothermal field on the Kilauea Lower East Rift Zone (KLERZ) also showed a lack of surface CO2 flux signals, however aqueous geochemistry indicated contribution of magmatic CO2 and He to shallow groundwater here. As magma has been intercepted in geothermal drilling at the Puna field, the lack of measured surface CO2 flux indicative of upflow of magmatic fluids here is likely due to effective “scrubbing” by high groundwater and a mature hydrothermal system. Dissolved inorganic carbon (DIC) concentrations, δ13C compositions and 3He/4He values were sampled at Maui from several shallow


    Institute of Scientific and Technical Information of China (English)


    <正>20111936 Gao Yuyan(School of Earth Sciences and Resourses,China University of Geosciences,Beijing 100083,China);Wang Mingqi Study on the Geogas Composition of the Concealed Metal Deposit and Its Background Area:Taking Zhangquanzhuang Gold Deposit as an Example(Geological Survey and Research,ISSN1672-4135,CN12-1353/P,33(3),2010,p.198-206,4 illus.,6 tables,10 refs.)Key words:metal ores,geogas methods,Hebei ProvinceStudy on the ore-forming elements,trace elements,REE and their spatial distribution of the geogas in the Zhangquanzhuang gold deposit shows the anomaly compositions o

  7. Alaska Geochemical Database Version 2.0 (AGDB2) - Including "Best Value" Data Compilations for Geochemical Data for Rock, Sediment, Soil, Mineral, and Concentrate Sample Media (United States)

    U.S. Geological Survey, Department of the Interior — The Alaska Geochemical Database Version 2.0 (AGDB2) contains new geochemical data compilations in which each geologic material sample has one "best value"...

  8. Geochemical signature of columbite-tantalite and radiometric survey of radioactive pegmatites in the region of Parelhas, Rio Grande do Norte, Brazil; Assinatura geoquimica de columbita-tantalita e levantamento radiometrico de pegmatitos radioativos da regiao de Parelhas, RN, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Jorge Costa de


    This thesis is the result of geochemical, structural and radiometric investigations on radioactive pegmatites of the Borborema Pegmatitic Province in Northeast Brazil. The studied area, located in the surroundings of the city of Parelhas in the region of the Serra da Borborema, is well known for its thousands of pegmatitic bodies exploited in primitive mines called 'garimpos'. The main goal was to find an efficient, cheap and routine inspection procedure to identify the origin of commercialized radioactive columbite-tantalite (coltan) ore. The Brazilian Nuclear Energy Agency (CNEN) controls uranium commerce and nuclear activity in Brazil. Without an effective method to characterize coltan ores from different localities it is impossible to control the trade. The here presented new method was developed by correlating structural features of these pegmatites with the geochemical behavior of their coltan samples. It was found that the variation of the ratio U/Th versus Nb{sub 2}O{sub 5}/Ta{sub 2}O{sub 5} provides geochemical signatures (analytical fingerprints) for the source location of such ore. A test of the new method with coltan samples of commercial batches from the Brazilian states Amapa and Rondonia also generated distinct geochemical signatures. A radiometric survey (CPS) was carried out in several mines and pegmatites to study the environmental impact of gamma radiation. It included in situ measurements of pegmatite walls, host rocks, soil, and accumulated water and revealed that gamma emitters are hardly solubilized and environmental gamma radiation therefore generally is not enhanced to a dangerous level. (author)

  9. Geochemistry of rock samples from the National Geochemical Database (United States)

    U.S. Geological Survey, Department of the Interior — This data set contains geochemical data for rock samples collected by U.S. Geological Survey (USGS) personnel and analyzed either in the analytical laboratories of...

  10. Microbial iron cycling in acidic geothermal springs of Yellowstone National Park: Integrating molecular surveys, geochemical processes and isolation of novel Fe-active microorganisms

    Directory of Open Access Journals (Sweden)

    Mark A Kozubal


    Full Text Available Geochemical, molecular, and physiological analyses of microbial isolates were combined to study the geomicrobiology of acidic iron oxide mats in Yellowstone National Park (YNP. Nineteen sampling locations from 11 geothermal springs were studied ranging in temperature from 53 to 84 °C and pH 2.4 to 3.6. All iron-oxide mats exhibited high diversity of crenarchaeal sequences from the Sulfolobales, Thermoproteales, and Desulfurococcales. The predominant Sulfolobales sequences were highly similar to Metallosphaera yellowstonensis str. MK1, previously isolated from one of these sites. Other groups of archaea were consistently associated with different types of iron oxide mats, including undescribed members of the phyla Thaumarchaeota and Euryarchaeota. Bacterial sequences were dominated by relatives of Hydrogenobaculum spp. above 65-70 °C, but increased in diversity below 60 °C. Cultivation of relevant iron-oxidizing and iron-reducing microbial isolates included Sulfolobus str. MK3, Sulfobacillus str. MK2, Acidicaldus str. MK6, and a new candidate genus in the Sulfolobales referred to as Sulfolobales str. MK5. Strains MK3 and MK5 are capable of oxidizing ferrous iron autotrophically, while strain MK2 oxidizes iron mixotrophically. Similar rates of iron oxidation were observed for M. yellowstonensis str. MK1 and Sulfolobales str. MK5 cultures, and these rates are close to those measured in situ. Biomineralized phases of ferric iron varied among cultures and field sites, and included ferric oxyhydroxides, K-jarosite, goethite, hematite, and scorodite depending on geochemical conditions. Strains MK5 and MK6 are capable of reducing ferric iron under anaerobic conditions with complex carbon sources. The combination of geochemical and molecular data as well as physiological observations of isolates suggests that the community structure of acidic Fe mats is linked with Fe cycling across temperatures ranging from 53 to 88 oC.

  11. Management of Reclaimed Produced Water in the Rocky Mountain States Enhanced with the Expanded U.S. Geological Survey Produced Waters Geochemical Database (United States)

    Gans, K. D.; Blondes, M. S.; Reidy, M. E.; Conaway, C. H.; Thordsen, J. J.; Rowan, E. L.; Kharaka, Y. K.; Engle, M.


    The Rocky Mountain states; Wyoming, Colorado, Montana, New Mexico and Utah produce annually approximately 470,000 acre-feet (3.66 billion barrels) of produced water - water that coexists with oil and gas and is brought to the surface with the pumping of oil and gas wells. Concerns about severe drought, groundwater depletion, and contamination have prompted petroleum operators and water districts to examine the recycling of produced water. Knowledge of the geochemistry of produced waters is valuable in determining the feasibility of produced water reuse. Water with low salinity can be reclaimed for use inside and outside of the petroleum industry. Since a great proportion of petroleum wells in the Rocky Mountain states, especially coal-bed methane wells, have produced water with relatively low salinity (generally water could be important as a drought mitigation strategy, through the irrigation of farmland, blending of low salinity waters with existing drainage basins, re-use in the petroleum industry for hydraulic fracturing or enhanced oil recovery, and even for municipal uses, such as drinking water. The USGS Produced Waters Geochemical Database, available at, has 60,000 data points in this region (this includes 35,000 new data points added to the 2002 database) and will facilitate studies on the management of produced water for reclamation in the Rocky Mountain region. Expanding on the USGS 2002 database, which contains geochemical analyses of major ions and total dissolved solids, the new data also include geochemical analyses of minor ions and stable isotopes. We have added an interactive web map application which allows the user to filter data on chosen fields (e.g. TDS waters in water-constrained regions of the Rocky Mountains.

  12. The geochemical atlas of Alaska, 2016 (United States)

    Lee, Gregory K.; Yager, Douglas B.; Mauk, Jeffrey L.; Granitto, Matthew; Denning, Paul D.; Wang, Bronwen; Werdon, Melanie B.


    A rich legacy of geochemical data produced since the early 1960s covers the great expanse of Alaska; careful treatment of such data may provide significant and revealing geochemical maps that may be used for landscape geochemistry, mineral resource exploration, and geoenvironmental investigations over large areas. To maximize the spatial density and extent of data coverage for statewide mapping of element distributions, we compiled and integrated analyses of more than 175,000 sediment and soil samples from three major, separate sources: the U.S. Geological Survey, the National Uranium Resource Evaluation program, and the Alaska Division of Geological & Geophysical Surveys geochemical databases. Various types of heterogeneity and deficiencies in these data presented major challenges to our development of coherently integrated datasets for modeling and mapping of element distributions. Researchers from many different organizations and disparate scientific studies collected samples that were analyzed using highly variable methods throughout a time period of more than 50 years, during which many changes in analytical techniques were developed and applied. Despite these challenges, the U.S. Geological Survey has produced a new systematically integrated compilation of sediment and soil geochemical data with an average sample site density of approximately 1 locality per 10 square kilometers (km2) for the entire State of Alaska, although density varies considerably among different areas. From that compilation, we have modeled and mapped the distributions of 68 elements, thus creating an updated geochemical atlas for the State.

  13. 珠江三角洲经济区生态地球化学评价%Eco-geochemical Survey and Assessment in Pearl River Delta Economic Zone,Guangdong Province,China

    Institute of Scientific and Technical Information of China (English)

    窦磊; 杜海燕; 游远航; 赖启宏


    Soil heavy metal pollution is one of the main environmental problems in Pearl River Delta Economic Zone,which directly threatens the stability of regional ecosystem and food safety,and has profound influences on economic sustainability,especially for sustainable agriculture and people’s health.Consequently,soil envi-ronment quality and food safety in this region have receiving extensive attention from all around China.Based on multi-purpose regional geochemical survey,regional eco-geochemical assessment,local eco-geochemical assess-ment and comprehensive appraisal,the eco-geochemical survey and assessment in Pearl River Delta Economic Zone of 47,954 km2 (including the area of 10 m depth in shallow inshore waters)was completed.Samples of soil,sediments of intertidal and major rivers in the region were collected in accordance with the two-layer grid method.Totally 71 elements and indicators for soils and sediments were determined and it is the first time to study the geochemical characteristics of the Pearl River Delta region.On the basis of the regional survey,the samples of rock,soil,sediment,dust,water,biology,human hair and other types of media samples in signifi-cant zone were systemic collected.The composition,distribution characteristics,sources,impact mechanisms and ecological security,migration and transformation process of toxic elements and nutrition elements in signifi-cant zone were investigated through case research and general analysis.According to the characteristics of the area,we firstly carried out the study of geochemical character of delta formation evolution and formulation of en-vironmental quality standards for soils in the Pearl River Delta region.%土壤重金属污染是珠江三角洲地区主要的生态环境问题之一,直接影响到区域生态系统的稳定和食品安全。通过开展多目标区域地球化学调查、区域生态地球化学评价、局部生态地球化学评价和总体综合评价,系统完成

  14. Management of Water for Unconventional Oil and Gas Operations Enhanced with the Expanded U.S.Geological Survey Produced Waters Geochemical Database (United States)

    Gans, K. D.; Blondes, M. S.; Thordsen, J. J.; Thomas, B.; Reidy, M. E.; Engle, M.; Kharaka, Y. K.; Rowan, E. L.


    municipalities and citizens can determine the geochemical nature of deep groundwater supplies, contamination sources, and impacts of hydraulic fracturing. Energy companies can utilize the database for determining the suitability of water reuse and for identifying regions where non-potable hydraulic fracturing water may be obtainable.

  15. Alaska Geochemical Database (AGDB)-Geochemical data for rock, sediment, soil, mineral, and concentrate sample media (United States)

    Granitto, Matthew; Bailey, Elizabeth A.; Schmidt, Jeanine M.; Shew, Nora B.; Gamble, Bruce M.; Labay, Keith A.


    The Alaska Geochemical Database (AGDB) was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This Microsoft Access database serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed in USGS laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects from 1962 to 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy mineral concentrate samples are included in this database. The AGDB includes historical geochemical data originally archived in the USGS Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the USGS PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. This arduous process of reviewing, verifying and, where necessary, editing all USGS geochemical data resulted in a significantly improved Alaska geochemical dataset. USGS data that were not previously in the NGDB because the data predate the earliest USGS geochemical databases, or were once excluded for programmatic reasons

  16. Geochemical Calculations Using Spreadsheets. (United States)

    Dutch, Steven Ian


    Spreadsheets are well suited to many geochemical calculations, especially those that are highly repetitive. Some of the kinds of problems that can be conveniently solved with spreadsheets include elemental abundance calculations, equilibrium abundances in nuclear decay chains, and isochron calculations. (Author/PR)

  17. Regional Geochemical Division-A Tool for Delineating Geochemical Block

    Institute of Scientific and Technical Information of China (English)


    Regional geochemical division is a mapping technique to divide an area into slices where the associations between geochemical elements are relatively simple and uniform. The result of division is expressed on a 2-D map. The scheme of regional geochemical division includes non-supervised pattern recognition, elementary statistics and factor analysis. A practical example in a gold prospecting area in Jilin, China, and the corresponding explanation are presented. Regional geochemical division is a basic approach to the delineation of the geochemical blocks as well.

  18. Identification of Geochemical Anomaly by Multifractal Analysis

    Institute of Scientific and Technical Information of China (English)

    Xie Shuyun; Cheng Qiuming; Ke Xianzhong; Bao Zhengyu; Wang Changming; Quan Haoli


    The separation of anomalies from geochemical background is an important part of data analysis because lack of such identifications might have profound influence on or even distort the final analysis results. In this article, 1 672 geochemical analytical data of 11 elements, including Cu, Mo, Ag, Sn, and others, from a region within Tibet, South China, are used as one example. Together with the traditional anomaly recognition method of using the iterative mean ±2σ, local multifractality theory has been utilized to delineate the ranges of geochemical anomalies of the elements. To different degrees, on the basis of original data mapping, C-A fractal analysis and singularity exponents, Sn differs from the other 10 elements. Moreover, geochemical mapping results based on values of the multifractal asymmetry index for all elements delineate the highly anomalous area. Similar to other 10 elements, the anomalous areas of Sn delineated by the asymmetry index distribute along the main structure orientations. According to the asymmetry indexes, the 11 elements could be classified into 3 groups: (1) Ag and Au, (2) As-Sb-Cu-Pb-Zn-Mo, and (3) Sn-Bi-W.This paragenetic association of elements can be used to interpret possible origins of mineralization, which is in agreement with petrological analysis and field survey results.

  19. Geochemical baselines for the radioelements K, U, and Th in the Campania region, Italy: a comparison of stream-sediment geochemistry and gamma-ray surveys

    Energy Technology Data Exchange (ETDEWEB)

    Lima, A. [Dipartimento di Geofisica e Vulcanologia, Universita di Napoli ' Federico II' , Via Mezzocannone 8, 80134 Naples (Italy)]. E-mail:; Albanese, S. [Dipartimento di Geofisica e Vulcanologia, Universita di Napoli ' Federico II' , Via Mezzocannone 8, 80134 Naples (Italy); Cicchella, D. [Dipartimento di Geofisica e Vulcanologia, Universita di Napoli ' Federico II' , Via Mezzocannone 8, 80134 Naples (Italy)


    This paper presents new data on the baseline concentrations of U, Th and K in 2389 stream sediments over the whole Campania region. These data, based on systematic sampling and analysis, are compared with those obtained by gamma-ray spectrometry surveys. Variations in the U, Th and K concentration in the surficial environment of the Campania region appear to be related to bedrock lithology. Generally, high U, Th and K values in stream sediments correspond well with the occurrence of volcanic rocks in the central-western part of the region, whereas low values are found in areas characterized by silico-clastic and carbonate deposits, occurring mostly in the southern and eastern part of the region. Gamma-ray spectrometry maps show a similar pattern, although the distribution of the highest radioactivity levels define more restricted areas than the ones resulting from mapping stream sediment geochemistry. Particularly high {sup 40}K radioactivity levels delimit all the known eruptive centers (Roccamonfina, Campi Flegrei and Somma-Vesuvius), including the fissural sources of Campania Ignimbrites, much better than U and Th radioactivity. One of the concerns for human health in the Campania region is the total gamma radiation and Rn potential related mostly to alkaline volcanics of the Neapolitan volcanological province. In particular, geothermal activity occurring in all the Campanian volcanic areas represents a potential hazard for Rn gas.

  20. The level of air pollution in the impact zone of coal-fired power plant (Karaganda City) using the data of geochemical snow survey (Republic of Kazakhstan) (United States)

    Adil'bayeva, T. E.; Talovskaya, A. V.; Yazikov, Ye G.; Matveenko, I. A.


    Coal-fired power plants emissions impact the air quality and human health. Of great significance is assessment of solid airborne particles emissions from those plants and distance of their transportation. The article presents the results of air pollution assessment in the zone of coal-fired power plant (Karaganda City) using snow survey. Based on the mass of solid airborne particles deposited in snow, time of their deposition on snow at the distance from 0.5 to 4.5 km a value of dust load has been determined. It is stated that very high level of pollution is observed at the distance from 0.5 to 1 km. there is a trend in decrease of dust burden value with the distance from the stacks of coal-fired power plant that may be conditioned by the particle size and washing out smaller ash particles by ice pellets forming at freezing water vapour in stacks of the coal-fired power plant. Study in composition of solid airborne particles deposited in snow has shown that they mainly contain particulates of underburnt coal, Al-Si- rich spheres, Fe-rich spheres, and coal dust. The content of the particles in samples decreases with the distance from the stacks of the coal-fired power plant.

  1. Major- and Trace-Element Concentrations in Soils from Two Geochemical Surveys (1972 and 2005) of the Denver, Colorado, Metropolitan Area (United States)

    Kilburn, James E.; Smith, David B.; Closs, L. Graham; Smith, Steven M.


    Introduction This report contains major- and trace-element concentration data for soil samples collected in 1972 and 2005 from the Denver, Colorado, metropolitan area. A total of 405 sites were sampled in the 1972 study from an area approximately bounded by the suburbs of Golden, Thornton, Aurora, and Littleton to the west, north, east, and south, respectively. This data set included 34 duplicate samples collected in the immediate vicinity of the primary sample. In 2005, a total of 464 sites together with 34 duplicates were sampled from the same approximate localities sampled in 1972 as well as additional sites in east Aurora and the area surrounding the Rocky Mountain Arsenal. Sample density for both surveys was on the order of 1 site per square mile. At each site, sample material was collected from a depth of 0-5 inches. Each sample collected was analyzed for near-total major- and trace-element composition by the following methods: (1) inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) for aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chromium, cobalt, copper, gallium, indium, iron, lanthanum, lead, lithium, magnesium, manganese, molybdenum, nickel, niobium, phosphorus, potassium, rubidium, scandium, silver, sodium, strontium, sulfur, tellurium, thallium, thorium, tin, titanium, tungsten, uranium, vanadium, yttrium, and zinc; and (2) hydride generation-atomic absorption spectrometry for selenium. The samples collected in 2005 were also analyzed by a cold vapor-atomic absorption method for mercury. This report makes available the analytical results of these studies.

  2. Geochemical modeling: a review

    Energy Technology Data Exchange (ETDEWEB)

    Jenne, E.A.


    Two general families of geochemical models presently exist. The ion speciation-solubility group of geochemical models contain submodels to first calculate a distribution of aqueous species and to secondly test the hypothesis that the water is near equilibrium with particular solid phases. These models may or may not calculate the adsorption of dissolved constituents and simulate the dissolution and precipitation (mass transfer) of solid phases. Another family of geochemical models, the reaction path models, simulates the stepwise precipitation of solid phases as a result of reacting specified amounts of water and rock. Reaction path models first perform an aqueous speciation of the dissolved constituents of the water, test solubility hypotheses, then perform the reaction path modeling. Certain improvements in the present versions of these models would enhance their value and usefulness to applications in nuclear-waste isolation, etc. Mass-transfer calculations of limited extent are certainly within the capabilities of state-of-the-art models. However, the reaction path models require an expansion of their thermodynamic data bases and systematic validation before they are generally accepted.

  3. DNA-based methods of geochemical prospecting (United States)

    Ashby, Matthew


    The present invention relates to methods for performing surveys of the genetic diversity of a population. The invention also relates to methods for performing genetic analyses of a population. The invention further relates to methods for the creation of databases comprising the survey information and the databases created by these methods. The invention also relates to methods for analyzing the information to correlate the presence of nucleic acid markers with desired parameters in a sample. These methods have application in the fields of geochemical exploration, agriculture, bioremediation, environmental analysis, clinical microbiology, forensic science and medicine.

  4. Geochemical baseline studies of soil in Finland (United States)

    Pihlaja, Jouni


    The soil element concentrations regionally vary a lot in Finland. Mostly this is caused by the different bedrock types, which are reflected in the soil qualities. Geological Survey of Finland (GTK) is carrying out geochemical baseline studies in Finland. In the previous phase, the research is focusing on urban areas and mine environments. The information can, for example, be used to determine the need for soil remediation, to assess environmental impacts or to measure the natural state of soil in industrial areas or mine districts. The field work is done by taking soil samples, typically at depth between 0-10 cm. Sampling sites are chosen to represent the most vulnerable areas when thinking of human impacts by possible toxic soil element contents: playgrounds, day-care centers, schools, parks and residential areas. In the mine districts the samples are taken from the areas locating outside the airborne dust effected areas. Element contents of the soil samples are then analyzed with ICP-AES and ICP-MS, Hg with CV-AAS. The results of the geochemical baseline studies are published in the Finnish national geochemical baseline database (TAPIR). The geochemical baseline map service is free for all users via internet browser. Through this map service it is possible to calculate regional soil baseline values using geochemical data stored in the map service database. Baseline data for 17 elements in total is provided in the map service and it can be viewed on the GTK's web pages (

  5. [Microbial geochemical calcium cycle]. (United States)

    Zavarzin, G A


    The participation of microorganisms in the geochemical calcium cycle is the most important factor maintaining neutral conditions on the Earth. This cycle has profound influence on the fate of inorganic carbon, and, thereby, on the removal of CO2 from the atmosphere. The major part of calcium deposits was formed in the Precambrian, when prokaryotic biosphere predominated. After that, calcium recycling based on biogenic deposition by skeletal organisms became the main process. Among prokaryotes, only a few representatives, e.g., cyanobacteria, exhibit a special calcium function. The geochemical calcium cycle is made possible by the universal features of bacteria involved in biologically mediated reactions and is determined by the activities of microbial communities. In the prokaryotic system, the calcium cycle begins with the leaching of igneous rock predominantly through the action of the community of organotrophic organisms. The release of carbon dioxide to the soil air by organotrophic aerobes leads to leaching with carbonic acid and soda salinization. Under anoxic conditions, of major importance is the organic acid production by primary anaerobes (fermentative microorganisms). Calcium carbonate is precipitated by secondary anaerobes (sulfate reducers) and to a smaller degree by methanogens. The role of the cyanobacterial community in carbonate deposition is exposed by stromatolites, which are the most common organo-sedimentary Precambrian structures. Deposition of carbonates in cyanobacterial mats as a consequence of photoassimilation of CO2 does not appear to be a significant process. It is argued that carbonates were deposited at the boundary between the "soda continent", which emerged as a result of subaerial leaching with carbonic acid, and the ocean containing Ca2+. Such ecotones provided favorable conditions for the development of the benthic cyanobacterial community, which was a precursor of stromatolites.

  6. The geochemical Phenomenon-Local geochemical fields in a glacier (scientific note)


    V. N., Makarov


    Geochemical fields in alpine cold and warm glaciers were studied. Local geochemical fields of typomorphic elements were found to form in the ice and on the surface of glaciers overlying ore bodies and endogenic geochemical haloes. The formation of local cryogenic geochemical fields in the glaciers results from sharp geochemical heterogeneity and geochemical processes in underlying rocks which cause cryogenic migration of chemical elements and compounds in the glacier. The thickness of geochem...

  7. The geochemical Phenomenon-Local geochemical fields in a glacier (scientific note)


    V. N., Makarov


    Geochemical fields in alpine cold and warm glaciers were studied. Local geochemical fields of typomorphic elements were found to form in the ice and on the surface of glaciers overlying ore bodies and endogenic geochemical haloes. The formation of local cryogenic geochemical fields in the glaciers results from sharp geochemical heterogeneity and geochemical processes in underlying rocks which cause cryogenic migration of chemical elements and compounds in the glacier. The thickness of geochem...

  8. Evaluation of geochemical data acquired from regular grids

    Energy Technology Data Exchange (ETDEWEB)

    Bezvoda, V.; Jelinkova, E.; Segeth, K.


    Geochemical data obtained during mineral exploration often are biased by systematic as well as random errors; these may result in failures when usual methods of evaluation are used. This is true particularly in soil surveys carried out in regions where a long history of prospecting and mining activity has occurred and/or where aerial chemical pollution is likely to have occurred. A satisfactory evaluation of geochemical data even in such an unfavorable case requires sampling on a relatively dense grid and utilization of all available knowledge of types of mineralization. The evaluation procedure proposed consists of five consecutive phases: (1) dividing the area of interest into subareas of a relatively homogeneous geological nature; (2) processing by multivariate methods (factor analysis, in particular) without consideration of geographic relations; (3) a preliminary interpretation and search for a geochemical explanation of factors; (4) processing of individual factors in two-dimensional geographic space by directional and frequency linear filtering methods; (5) final interpretation and construction of a geochemical model. The procedure is illustrated by an example from a geochemical exploration survey in the vicinity of Pribram (Middle Bohemia).

  9. Oil samples and geochemical analyses of Afghanistan and adjacent areas (oilafg.shp) (United States)

    U.S. Geological Survey, Department of the Interior — This shapefile contains points that describe the location of oil samples collected in Afghanistan and adjacent areas, and the results of organic geochemical analysis.

  10. Geochemical and mineralogical maps for soils of the conterminous United States (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical and mineralogical maps along with a histogram, boxplot, and empirical cumulative distribution function plot for each element or mineral whose data are...

  11. Geochemical and mineralogical data for soils of the conterminous United States (United States)

    U.S. Geological Survey, Department of the Interior — In 2007, the U.S. Geological Survey began a low-density (1 site per 1,600 sq. km., 4857 sites) geochemical and mineralogical survey of soils of the conterminous...

  12. Alaska Geochemical Database - Mineral Exploration Tool for the 21st Century - PDF of presentation (United States)

    Granitto, Matthew; Schmidt, Jeanine M.; Labay, Keith A.; Shew, Nora B.; Gamble, Bruce M.


    The U.S. Geological Survey has created a geochemical database of geologic material samples collected in Alaska. This database is readily accessible to anyone with access to the Internet. Designed as a tool for mineral or environmental assessment, land management, or mineral exploration, the initial version of the Alaska Geochemical Database - U.S. Geological Survey Data Series 637 - contains geochemical, geologic, and geospatial data for 264,158 samples collected from 1962-2009: 108,909 rock samples; 92,701 sediment samples; 48,209 heavy-mineral-concentrate samples; 6,869 soil samples; and 7,470 mineral samples. In addition, the Alaska Geochemical Database contains mineralogic data for 18,138 nonmagnetic-fraction heavy mineral concentrates, making it the first U.S. Geological Survey database of this scope that contains both geochemical and mineralogic data. Examples from the Alaska Range will illustrate potential uses of the Alaska Geochemical Database in mineral exploration. Data from the Alaska Geochemical Database have been extensively checked for accuracy of sample media description, sample site location, and analytical method using U.S. Geological Survey sample-submittal archives and U.S. Geological Survey publications (plus field notebooks and sample site compilation base maps from the Alaska Technical Data Unit in Anchorage, Alaska). The database is also the repository for nearly all previously released U.S. Geological Survey Alaska geochemical datasets. Although the Alaska Geochemical Database is a fully relational database in Microsoft® Access 2003 and 2010 formats, these same data are also provided as a series of spreadsheet files in Microsoft® Excel 2003 and 2010 formats, and as ASCII text files. A DVD version of the Alaska Geochemical Database was released in October 2011, as U.S. Geological Survey Data Series 637, and data downloads are available at Also, all Alaska Geochemical Database data have been incorporated into

  13. SURVEY

    DEFF Research Database (Denmark)

    SURVEY er en udbredt metode og benyttes inden for bl.a. samfundsvidenskab, humaniora, psykologi og sundhedsforskning. Også uden for forskningsverdenen er der mange organisationer som f.eks. konsulentfirmaer og offentlige institutioner samt marketingsafdelinger i private virksomheder, der arbejder...... med surveys. Denne bog gennemgår alle surveyarbejdets faser og giver en praktisk indføring i: • design af undersøgelsen og udvælgelse af stikprøver, • formulering af spørgeskemaer samt indsamling og kodning af data, • metoder til at analysere resultaterne...

  14. NOAA and MMS Marine Minerals Geochemical Database (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Minerals Geochemical Database was created by NGDC as a part of a project to construct a comprehensive computerized bibliography and geochemical database...

  15. Geochemical Modeling of Carbon Sequestration, MMV, and EOR in the Illinois Basin (United States)

    Berger, P.M.; Roy, W.R.; Mehnert, E.


    The Illinois State Geologic Survey is conducting several ongoing CO2 sequestration projects that require geochemical models to gain an understanding of the processes occurring in the subsurface. The ISGS has collected brine and freshwater samples associated with an enhanced oil recovery project in the Loudon oil field. Geochemical modeling allows us to understand reactions with carbonate and silicate minerals in the reservoir, and the effects they have had on brine composition. For the Illinois Basin Decatur project, geochemical models should allow predictions of the reactions that will take place before CO2 injection begins. ?? 2009 Elsevier Ltd. All rights reserved.

  16. A geochemical atlas of North Carolina, USA (United States)

    Reid, J.C.


    A geochemical atlas of North Carolina, U.S.A., was prepared using National Uranium Resource Evaluation (NURE) stream-sediment data. Before termination of the NURE program, sampling of nearly the entire state (48,666 square miles of land area) was completed and geochemical analyses were obtained. The NURE data are applicable to mineral exploration, agriculture, waste disposal siting issues, health, and environmental studies. Applications in state government include resource surveys to assist mineral exploration by identifying geochemical anomalies and areas of mineralization. Agriculture seeks to identify areas with favorable (or unfavorable) conditions for plant growth, disease, and crop productivity. Trace elements such as cobalt, copper, chromium, iron, manganese, zinc, and molybdenum must be present within narrow ranges in soils for optimum growth and productivity. Trace elements as a contributing factor to disease are of concern to health professionals. Industry can use pH and conductivity data for water samples to site facilities which require specific water quality. The North Carolina NURE database consists of stream-sediment samples, groundwater samples, and stream-water analyses. The statewide database consists of 6,744 stream-sediment sites, 5,778 groundwater sample sites, and 295 stream-water sites. Neutron activation analyses were provided for U, Br, Cl, F, Mn, Na, Al, V, Dy in groundwater and stream water, and for U, Th, Hf, Ce, Fe, Mn, Na, Sc, Ti, V, Al, Dy, Eu, La, Sm, Yb, and Lu in stream sediments. Supplemental analyses by other techniques were reported on U (extractable), Ag, As, Ba, Be, Ca, Co, Cr, Cu, K, Li, Mg, Mo, Nb, Ni, P, Pb, Se, Sn, Sr, W, Y, and Zn for 4,619 stream-sediment samples. A small subset of 334 stream samples was analyzed for gold. The goal of the atlas was to make available the statewide NURE data with minimal interpretation to enable prospective users to modify and manipulate the data for their end use. The atlas provides only

  17. The Geochemical Society(GS)

    Institute of Scientific and Technical Information of China (English)

    Seth M.Davis


    @@ Mission The Geochemical Society is an international nonprofit organization for scientists involved in the practice,study and teaching of geochemistry.0ur principal roles are to understand and meet the needs of our members so as to provide them with programs and services that will help them be better geochemists;to empower geochemists through information,education,relationships and resources that will enrich their professional development and careers;and to advance the thought and application of geochemistry.

  18. Geochemical Investigations of Groundwater Stability

    Energy Technology Data Exchange (ETDEWEB)

    Bath, Adrian [Intellisci Ltd., Loughborough (United Kingdom)


    The report describes geochemical parameters and methods that provide information about the hydrodynamic stability of groundwaters in low permeability fractured rocks that are potential hosts for radioactive waste repositories. Hydrodynamic stability describes the propensity for changes in groundwater flows over long timescales, in terms of flow rates and flow directions. Hydrodynamic changes may also cause changes in water compositions, but the related issue of geochemical stability of a potential repository host rock system is outside the scope of this report. The main approaches to assessing groundwater stability are numerical modelling, measurement and interpretation of geochemical indicators in groundwater compositions, and analyses and interpretations of secondary minerals and fluid inclusions in these minerals. This report covers the latter two topics, with emphasis on geochemical indicators. The extent to which palaeohydrogeology and geochemical stability indicators have been used in past safety cases is reviewed. It has been very variable, both in terms of the scenarios considered, the stability indicators considered and the extent to which the information was explicitly or implicitly used in assessing FEPs and scenarios in the safety cases. Geochemical indicators of hydrodynamic stability provide various categories of information that are of hydrogeological relevance. Information about groundwater mixing, flows and water sources is potentially provided by the total salinity of groundwaters, their contents of specific non-reactive solutes (principally chloride) and possibly of other solutes, the stable isotopic ratio of water, and certain characteristics of secondary minerals and fluid inclusions. Information pertaining directly to groundwater ages and the timing of water and solute movements is provided by isotopic systems including tritium, carbon-14, chlorine-36, stable oxygen and hydrogen isotopes, uranium isotopes and dissolved mobile gases in

  19. Discussion on the Geochemical Survey Datum Processing Method:An Example from 1/20 0000 Geochemical Survey Datum of the Xiguitu Area, Da Hinggan Mountains%关于地球化学数据处理方法的讨论-以大兴安岭喜桂图地区1/20万区域地球化学数据为例

    Institute of Scientific and Technical Information of China (English)

    戴慧敏; 刘希瑶; 董北; 郑春颖


    To eliminate the contour distortion or"bull's-eye point"existing in the geochemical map of the outlier data points, this paper used different data grid interpolation methods and parameter models. The results show that the kriging, radial basis function, modified shepard’s method, minimum curvature and moving average method can’t eliminate the phenomenon. The geochemical contour map and cross validation results with demonstrate var-ious grid algorithm programming demonstrate that the distance exponential reverse weighted method is the most ideal method,and choosing to sampling spacing as the grid spacing, 2.5 times the grid spacing as the search radi-us and distance power exponent can eliminate the contour distortion or"bull's-eye point"phenomenon. This grid method and parameters can also express closer to the original data. The comparison result above can provide in-formation for the similar problems during the datum processing.%针对地球化学数据中存在的离群数据点在地球化学图面上出现的等量线畸变或“牛眼点”现象,本文使用多种数据网格化插值方法和参数对比以消除“公牛眼”现象,结果表明,克里格、径向基本函数、改进的谢别德、最小曲率、移动平均等方法均不能较好地消除该现象。各种网格化算法编制的地球化学等量线图和交叉验证结果证明,以改进的指数距离幂倒数加权网格化方法效果最好,并且网格参数选择中以取样间距为网格间距,以2.5倍网格间距为搜索半径和幂指数因子的网格化参数既能消除等量线畸变现象,又能对原始数据进行较接近的表达。上述各种地球化学数据网格化插值方法的对比及结果可为地球化学数据处理中遇到同类问题提供信息。

  20. Geochemical and geostatistical evaluation, Arkansas Canyon Planning Unit, Fremont and Custer Counties, Colorado (United States)

    Weiland, E.F.; Connors, R.A.; Robinson, M.L.; Lindemann, J.W.; Meyer, W.T.


    A mineral assessment of the Arkansas Canyon Planning Unit was undertaken by Barringer Resources Inc., under the terms of contract YA-553-CTO-100 with the Bureau of Land Management, Colorado State Office. The study was based on a geochemical-geostatistical survey in which 700 stream sediment samples were collected and analyzed for 25 elements. Geochemical results were interpreted by statistical processing which included factor, discriminant, multiple regression and characteristic analysis. The major deposit types evaluated were massive sulfide-base metal, sedimentary and magmatic uranium, thorium vein, magmatic segregation, and carbonatite related deposits. Results of the single element data and multivariate geostatistical analysis indicate that limited potential exists for base metal mineralization near the Horseshoe, El Plomo, and Green Mountain Mines. Thirty areas are considered to be anomalous with regard to one or more of the geochemical parameters evaluated during this study. The evaluation of carbonatite related mineralization was restricted due to the lack of geochemical data specific to this environment.

  1. Central Colorado Assessment Project (CCAP)-Geochemical data for rock, sediment, soil, and concentrate sample media (United States)

    Granitto, Matthew; DeWitt, Ed H.; Klein, Terry L.


    This database was initiated, designed, and populated to collect and integrate geochemical data from central Colorado in order to facilitate geologic mapping, petrologic studies, mineral resource assessment, definition of geochemical baseline values and statistics, environmental impact assessment, and medical geology. The Microsoft Access database serves as a geochemical data warehouse in support of the Central Colorado Assessment Project (CCAP) and contains data tables describing historical and new quantitative and qualitative geochemical analyses determined by 70 analytical laboratory and field methods for 47,478 rock, sediment, soil, and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed either in the analytical laboratories of the USGS or by contract with commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects. In addition, geochemical data from 7,470 sediment and soil samples collected and analyzed under the Atomic Energy Commission National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program (henceforth called NURE) have been included in this database. In addition to data from 2,377 samples collected and analyzed under CCAP, this dataset includes archived geochemical data originally entered into the in-house Rock Analysis Storage System (RASS) database (used by the USGS from the mid-1960s through the late 1980s) and the in-house PLUTO database (used by the USGS from the mid-1970s through the mid-1990s). All of these data are maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB and from the NURE database were used to generate most of this dataset. In addition, USGS data that have been excluded previously from the NGDB because the data predate earliest USGS geochemical databases, or were once excluded for programmatic reasons

  2. TAPIR--Finnish national geochemical baseline database. (United States)

    Jarva, Jaana; Tarvainen, Timo; Reinikainen, Jussi; Eklund, Mikael


    In Finland, a Government Decree on the Assessment of Soil Contamination and Remediation Needs has generated a need for reliable and readily accessible data on geochemical baseline concentrations in Finnish soils. According to the Decree, baseline concentrations, referring both to the natural geological background concentrations and the diffuse anthropogenic input of substances, shall be taken into account in the soil contamination assessment process. This baseline information is provided in a national geochemical baseline database, TAPIR, that is publicly available via the Internet. Geochemical provinces with elevated baseline concentrations were delineated to provide regional geochemical baseline values. The nationwide geochemical datasets were used to divide Finland into geochemical provinces. Several metals (Co, Cr, Cu, Ni, V, and Zn) showed anomalous concentrations in seven regions that were defined as metal provinces. Arsenic did not follow a similar distribution to any other elements, and four arsenic provinces were separately determined. Nationwide geochemical datasets were not available for some other important elements such as Cd and Pb. Although these elements are included in the TAPIR system, their distribution does not necessarily follow the ones pre-defined for metal and arsenic provinces. Regional geochemical baseline values, presented as upper limit of geochemical variation within the region, can be used as trigger values to assess potential soil contamination. Baseline values have also been used to determine upper and lower guideline values that must be taken into account as a tool in basic risk assessment. If regional geochemical baseline values are available, the national guideline values prescribed in the Decree based on ecological risks can be modified accordingly. The national geochemical baseline database provides scientifically sound, easily accessible and generally accepted information on the baseline values, and it can be used in various

  3. Proceedings of the workshop on geochemical modeling

    Energy Technology Data Exchange (ETDEWEB)


    The following collection of papers was presented at a workshop on geochemical modeling that was sponsored by the Office of Civilian Radioactive Waste Management Program at the Lawrence Livermore National Laboratory (LLNL). The LLNL Waste Management Program sponsored this conference based on their belief that geochemical modeling is particularly important to the radioactive waste disposal project because of the need to predict the consequences of long-term water-rock interactions at the proposed repository site. The papers included in this volume represent a subset of the papers presented at the Fallen Leaf Lake Conference and cover a broad spectrum of detail and breadth in a subject that reflects the diverse research interests of the conference participants. These papers provide an insightful look into the current status of geochemical modeling and illustrate how various geochemical modeling codes have been applied to problems of geochemical interest. The emphasis of these papers includes traditional geochemical modeling studies of individual geochemical systems, the mathematical and theoretical development and refinement of new modeling capabilities, and enhancements of data bases on which the computations are based. The papers in this proceedings volume have been organized into the following four areas: Geochemical Model Development, Hydrothermal and Geothermal Systems, Sedimentary and Low Temperature Environments, and Data Base Development. The participants of this symposium and a complete list of the talks presented are listed in the appendices.

  4. Use of Geochemical Indices in Environmental Assessment of Soil; the Predictable and the Predictably Unpredictable (United States)

    Mikkonen, Hannah; Clarke, Bradley; van de Graaff, Robert; Reichman, Suzie


    Geochemical correlations between common contaminants (Pb, Ni, As, Cr, Co and Zn) and earth metals, Fe and Mn, have been recommended as empirical tools to estimate "background" concentrations of metals in soil. A limited number of studies indicate that geochemical ratios between Pb, Ni, As, Cr, Co, V and Zn with scavenger metals Fe or Mn, are consistent between soils collected from different regions (Hamon et al. 2004, Myers and Thorbjornsen 2004). These studies have resulted in the incorporation of geochemical indices into Australian guidance, for derivation of ecological investigation levels for Ni, Cr, Cu and Zn. However, little research has been undertaken to assess the variation of geochemical patterns between soils derived from different parent materials or different weathering environments. A survey of background soils derived from four different parent materials, across Victoria, Australia, was undertaken, comprising collection of samples (n=640) from the surface (0 to 0.1 m) and sub-surface (0.3 to 0.6 m). Soil samples were collected from urban and rural areas of low disturbance, away from point sources of contamination. Samples were analysed for metals/metalloids and soil physical and chemical properties. Statistical review of results included regression and multivariate analysis. The results of the soil survey were compared against geochemical relationships reported within Australia and internationally. Compilation of results from this study and international data sets, indicates that geochemical relationships for metals Cr and V (in the format of log[Cr] = alog[Fe] +c) are predictable, not only between soils derived from different parent materials, but also between soils of different continents. Conversely, relationships between Zn and Fe, Pb and Fe, Cu and Fe, Co and Mn are variable, particularly within soils derived from alluvial sediments, which may have undergone periods of reducing conditions, resulting in dissociation from metal oxides. Broad

  5. Application of the 'fingerprint' geochemical method in a geothermal exploration survey of the Sumikawa area. Fingerprint ho no chinetsu tansaho to shite no yukosei ni tsuite (Akitaken sumikawa chiku deno chosarei)

    Energy Technology Data Exchange (ETDEWEB)

    Noda, T.; Takahashi, M.; Shigeno, H. (Geological Survey of Japan, Tsukuba (Japan))


    This paper presents an affirmative conclusion on the effectiveness of a Fingerprint method as a method to explore geothermal sources based on results of the survey conducted in the Sumikawa Area in Akita Prefecture. The soil gas samples from the area are classified into clusters of three kinds according to patterns in the mass spectra, and four types according to characteristics of the highly divergent components. It is shown that a distribution chart of the samples belonging to each type classified in the survey area presents a distribution that expresses well significantly the degree of activeness in geothermal activities Also shown is that the areas in which the samples of each type exist can be distinguished without a duplication a chart plotting the relationship between a total gas divergent amount'' and an average gas mass number'' by samples (a gas characteristics identifying chart). It is further indicated that the type classification according to highly divergent components and the cluster classification based on the mass spectra patterns result in a conclusion that the classifications have similarity in their descriptions. 17 refs., 11 figs., 4 tabs.

  6. Role of geochemical background at evaluation of investment attractiveness of recreational territories

    Directory of Open Access Journals (Sweden)

    Vdovina Ol'ga Konstantinovna


    Full Text Available The article shows the role of natural geochemical background when estimating investment attractiveness of recreational areas. It is noted, that geochemical background influence on people's sickness rate isn't considered now. Though it's understood, that even insignificant increase of geochemical background in relation to percentage abundance of Earth crest may lead to endemic diseases of people, animals and plants. An indicator of geochemical endemicity areas was proposed for assessing the impact of storage elements and of a lack of geological environment on human health. Thanks to this measure, and taking into account landscape features of the area, the authors allocated lands, dangerous and potentially dangerous in terms of endemicity. The importance of ratings was achieved by the use of those factors that could have a great influence on the cost of land development. This includes, first of all, the factors that affect population health, and economic and geographic factors that minimize the cost of the territory development and the factors that give rise to financial risks and risks of human losses. The main risk factors include: potential ecological and geochemical risk; high absolute heights, development and activity of dangerous geological processes and phenomena. Systemacity of researches was reached by using factors, that characterize the object from different aspects; readiness of area infrastructure to its exploration and possible risks. Objectivity was achieved by the use of figures obtained from the results of geochemical and engineering surveys with their metrological support.

  7. A New Geochemical Reaction Model for Groundwater Systems

    Institute of Scientific and Technical Information of China (English)


    Through a survey of the literature on geology, hydrogeology and hydrogeochemistry, this paper presents a hydrogeochemical model for the groundwater system in a dross-dumping area of the Shandong Aluminium Plant. It is considered that the groundwater-bearing medium is a mineral aggregate and that the interactions between groundwater and the groundwater-bearing medium can be described as a series of geochemical reactions. On that basis, the principle of minimum energy and the equations of mass balance, electron balance and electric neutrality are applied to construct a linear programming mathematical model for the calculation of mass transfer between water and rock with the simplex method.

  8. Geophysical and geochemical characterisation of groundwater resources in Western Zambia

    DEFF Research Database (Denmark)

    Chongo, Mkhuzo; Banda, Kawawa Eddy; Bauer-Gottwein, Peter

    both ground-based and airborne geophysical methods as well as extensive water quality sampling. The occurrence of saline groundwater follows a clear spatial pattern and appears to be related to the palaeo Lake Makgadikgadi, whose northernmost extension reached into the Machile area. Because the lake...... precipitation has formed limited freshwater reservoirs in a generally saline area, which need to be sustainably managed. We will present initial results from the geophysical and geochemical surveys conducted over the past few years. We will interpret these findings in terms of the geologic history of Southern...

  9. Alaska Geochemical Database, Version 2.0 (AGDB2)--including “best value” data compilations for rock, sediment, soil, mineral, and concentrate sample media (United States)

    Granitto, Matthew; Schmidt, Jeanine M.; Shew, Nora B.; Gamble, Bruce M.; Labay, Keith A.


    The Alaska Geochemical Database Version 2.0 (AGDB2) contains new geochemical data compilations in which each geologic material sample has one “best value” determination for each analyzed species, greatly improving speed and efficiency of use. Like the Alaska Geochemical Database (AGDB, before it, the AGDB2 was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This relational database, created from the Alaska Geochemical Database (AGDB) that was released in 2011, serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables in several different formats describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey personnel and analyzed in U.S. Geological Survey laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various U.S. Geological Survey programs and projects from 1962 through 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy-mineral concentrate samples are included in this database. The AGDB2 includes historical geochemical data originally archived in the U.S. Geological Survey Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the U.S. Geological Survey PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate

  10. Geochemical modelling baseline compositions of groundwater

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Kjøller, Claus; Andersen, Martin Søgaard;


    and variations in water chemistry that are caused by large scale geochemical processes taking place at the timescale of thousands of years. The most important geochemical processes are ion exchange (Valreas and Aveiro) where freshwater solutes are displacing marine ions from the sediment surface, and carbonate...... dissolution (East Midlands, Valreas and Aveiro). Reactive transport models, employing the code PHREEQC, which included these geochemical processes and one-dimensional solute transport were able to duplicate the observed patterns in water quality. These models may provide a quantitative understanding...

  11. Geologic and geochemical studies of the New Albany Shale Group (Devonian-Mississippian) in Illinois. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bergstrom, R.E.; Shimp, N.F.


    The Illinois State Geological Survey is conducting geological and geochemical investigations to evaluate the potential of New Albany Group shales as a source of hydrocarbons, particularly natural gas. Geological studies include stratigraphy and structure, mineralogic and petrographic characterization; analyses of physical properties; and development of a computer-based resources evaluation system. Geochemical studies include organic carbon content and trace elements; hydrocarbon content and composition; and adsorption/desorption studies of gas through shales. Separate abstracts have been prepared for each task reported.

  12. Major- and Trace-Element Concentrations in Soils from Northern California: Results from the Geochemical Landscapes Project Pilot Study (United States)

    Morrison, Jean M.; Goldhaber, Martin B.; Holloway, JoAnn M.; Smith, David B.


    In 2004, the U.S. Geological Survey (USGS), the Geological Survey of Canada (GSC), and the Mexican Geological Survey (Servicio Geologico Mexicano, or SGM) initiated pilot studies in preparation for a soil geochemical survey of North America called the Geochemical Landscapes Project. The purpose of this project is to provide a better understanding of the variability in chemical composition of soils in North America. The data produced by this survey will be used to construct baseline geochemical maps for regions within the continent. Two initial pilot studies were conducted: (1) a continental-scale study involving a north-south and east-west transect across North America and (2) a regional-scale study. The pilot studies were intended to test and refine sample design, sampling protocols, and field logistics for the full continental soils geochemical survey. Smith and others (2005) reported the results from the continental-scale pilot study. The regional-scale California study was designed to represent more detailed, higher resolution geochemical investigations in a region of particular interest that was identified from the low-sample-density continental-scale survey. A 20,000-km2 area of northern California (fig. 1), representing a wide variety of topography, climate, and ecoregions, was chosen for the regional-scale pilot study. This study area also contains diverse geology and soil types and supports a wide range of land uses including agriculture in the Sacramento Valley, forested areas in portions of the Sierra Nevada, and urban/suburban centers such as Sacramento, Davis, and Stockton. Also of interest are potential effects on soil geochemistry from historical hard rock and placer gold mining in the foothills of the Sierra Nevada, historical mercury mining in the Coast Range, and mining of base-metal sulfide deposits in the Klamath Mountains to the north. This report presents the major- and trace-element concentrations from the regional-scale soil geochemical

  13. Heavy Metal Pollution Assessment by Partial Geochemical ...

    African Journals Online (AJOL)


    sediments geochemical anomalies has been applied with success in .... pure exploration geological to environmental pollution studies as well as remote sensing ..... erosion of the amorphous phase to the sea in the form of suspension while ...

  14. Statistical Analysis Of Reconnaissance Geochemical Data From ...

    African Journals Online (AJOL)

    Statistical Analysis Of Reconnaissance Geochemical Data From Orle District, ... The univariate methods used include frequency distribution and cumulative ... The possible mineral potential of the area include base metals (Pb, Zn, Cu, Mo, etc.) ...

  15. Collected radiochemical and geochemical procedures

    Energy Technology Data Exchange (ETDEWEB)

    Kleinberg, J [comp.


    This revision of LA-1721, 4th Ed., Collected Radiochemical Procedures, reflects the activities of two groups in the Isotope and Nuclear Chemistry Division of the Los Alamos National Laboratory: INC-11, Nuclear and radiochemistry; and INC-7, Isotope Geochemistry. The procedures fall into five categories: I. Separation of Radionuclides from Uranium, Fission-Product Solutions, and Nuclear Debris; II. Separation of Products from Irradiated Targets; III. Preparation of Samples for Mass Spectrometric Analysis; IV. Dissolution Procedures; and V. Geochemical Procedures. With one exception, the first category of procedures is ordered by the positions of the elements in the Periodic Table, with separate parts on the Representative Elements (the A groups); the d-Transition Elements (the B groups and the Transition Triads); and the Lanthanides (Rare Earths) and Actinides (the 4f- and 5f-Transition Elements). The members of Group IIIB-- scandium, yttrium, and lanthanum--are included with the lanthanides, elements they resemble closely in chemistry and with which they occur in nature. The procedures dealing with the isolation of products from irradiated targets are arranged by target element.

  16. The effect of scale on the interpretation of geochemical anomalies (United States)

    Theobald, P.K.; Eppinger, R.G.; Turner, R.L.; Shiquan, S.


    The purpose of geochemical surveys changes with scale. Regional surveys identify areas where mineral deposits are most likely to occur, whereas intermediate surveys identify and prioritize specific targets. At detailed scales specific deposit models may be applied and deposits delineated. The interpretation of regional geochemical surveys must take into account scale-dependent difference in the nature and objectives of this type of survey. Overinterpretation of regional data should be resisted, as should recommendations to restrict intermediate or detailed follow-up surveys to the search for specific deposit types or to a too limited suite of elements. Regional surveys identify metallogenic provinces within which a variety of deposit types and metals are most likely to be found. At intermediate scale, these regional provinces often dissipate into discrete clusters of anomalous areas. At detailed scale, individual anomalous areas reflect local conditions of mineralization and may seem unrelated to each other. Four examples from arid environments illustrate the dramatic change in patterns of anomalies between regional and more detailed surveys. On the Arabian Shield, a broad regional anomaly reflects the distribution of highly differentiated anorogenic granites. A particularly prominent part of the regional anomaly includes, in addition to the usual elements related to the granites, the assemblage of Mo, W and Sn. Initial interpretation suggested potential for granite-related, stockwork Mo deposits. Detailed work identified three separate sources for the anomaly: a metal-rich granite, a silicified and stockwork-veined area with scheelite and molybdenite, and scheelite/powellite concentrations in skarn deposits adjacent to a ring-dike complex. Regional geochemical, geophysical and remote-sensing data in the Sonoran Desert, Mexico, define a series of linear features interpreted to reflect fundamental, northeast-trending fractures in the crust that served as the prime

  17. Organic geochemical constraints on paleoelevation (United States)

    Polissar, P. J.; Rowley, D. B.; Currie, B. S.; Freeman, K. H.


    The elevation history of the land surface is an important factor in the interpretation of past tectonic, climate and ecological processes. However, quantitative estimates of paleoelevation are difficult to produce and new techniques are needed. Organic geochemical approaches to quantifying paleoelevations provide a new perspective on this difficult task. The hydrogen isotopic composition of organic biomarker molecules synthesized by plants and algae is systematically related to the water used for growth. Organic molecules in ancient sediments can provide values for the isotopic composition of this water and thus elevation, provided the relationship between elevation and isotopic values is known. Molecular hydrogen isotope ratios from Cenozoic lake sediments on the Tibetan Plateau demonstrate the utility of a biomarker approach. Terrestrial plant-wax D/H values on Neogene sediments from the Namling-Oiyug Basin provide new paleoelevation estimates that compare well with previous studies. Plant wax D/H ratios paired with lacustrine carbonate oxygen isotope values from the Lunpola and Hoh-Xil basins illustrate how paired isotope systems can unravel the isotopic composition of precipitation from evaporative enrichment of lake waters. A potentially fruitful avenue for future research is illustrated by D/H analyses on older sediments from the Namling-Oiyug Basin. These sediments—like many that could be useful for paleoaltimetry—have experienced significant burial and heating. As temperatures approach the oil window it becomes possible to exchange hydrogen in both the extractable organic molecules (bitumen) and the insoluble organic residue (kerogen). The extent to which this exchange alters the original isotopic composition will determine the usefulness of D/H analyses on thermally mature organic matter. The potential payoff and pitfalls of D/H analyses on heated sediments is illustrated with thermally immature and mature samples from the Namling-Oiyug Basin.

  18. Geochemical Origin of Biological Molecules (United States)

    Bassez, Marie-Paule


    A model for the geochemical origin of biological molecules is presented. Rocks such as peridotites and basalts, which contain ferromagnesian minerals, evolve in the presence of water. Their hydrolysis is an exothermic reaction which generates heat and a release of H2 and of minerals with modified structures. The hydrogen reacts with the CO2 embedded inside the rock or with the CO2 of the environment to form CO in an hydrothermal process. With the N2 of the environment, and with an activation source arising from cosmic radiation, ferromagnesian rocks might evolve towards the abiotic formation of biological molecules, such as peptide like macromolecules which produce amino acids after acid hydrolysis. The reactions concerned are described. The production of hydrothermal CO is discussed in geological sites containing ferromagnesian silicate minerals and the low intensity of the Earth's magnetic field during Paleoarchaean Era is also discussed. It is concluded that excitation sources arising from cosmic radiation were much more abundant during Paleoarchaean Era and that macromolecular structures of biological relevance might consequently form during Archaean Eon, as a product of the chemical evolution of the rocks and of their mineral contents. This synthesis of abiotically formed biological molecules is consecutively discussed for meteorites and other planets such as Mars. This model for the geochemical origin of biological molecules has first been proposed in 2008 in the context of reactions involving catalysers such as kaolinite [Bassez 2008a] and then presented in conferences and articles [Bassez 2008b, 2009, 2012; Bassez et al. 2009a to 2012b]. BASSEZ M.P. 2008a Synthèse prébiotique dans les conditions hydrothermales, CNRIUT'08, Lyon 29-30/05/2008, Conf. and open access article: 29 mai 11h-12h40. BASSEZ M.P. 2008b Prebiotic synthesis under hydrothermal conditions, ISSOL'08, P2-6, Firenze-Italy, 24-29/08/2008. Poster at the

  19. Geochemical characteristics of Pingran area in Laos based on stream sediment survey and their prospecting signifivance%老挝平然地区水系沉积物测量地球化学特征及找矿意义

    Institute of Scientific and Technical Information of China (English)

    雷传扬; 李瑞峰; 赵保顺; 赵桂秋


    Pingran area is located in the Ma Jiang-Xam Nua island arc metallogenic belt, and the metallogenic condition of magmatic copper-nickel sulfide deposits is excellent. 1 ∶ 50 000 stream sediment survey around the Pingran area of Laos revealed an anomaly combination of multiple elements dominated by Cu, Ni and Co accompanied by Cr, V and Ti, reflecting the metallogenic specialization of the basic-ultrabasic rocks. The authors used the method of factor analysis and clustering to analyze the data of 1:50000 stream sedi-ment survey in Pingran area,and made a geological interpretation of the deposit. It is suggested that the anomalies from the geochemical survey are associated with the mineralization along a series of NW-trending fracture zones and the basic-ultrabasic rocks. Cluster analy-sis of the stream sediment geochemical data of Pingran area shows that fifteen kinds of trace elements can be grouped into three types, i.e. Ni, Cr, Cu, V, Co, Zn and Ti belong to the first type,As, Sb and Pb to the second type,and the rest to the third type. The first type reflects elemental distribution, accumulation characteristics and related mineralization information of mafic-ultramafic rocks, whereas the second type reflects the combination of ore-forming elements at low-medium temperature. The primary factor of stream sedi-ment geochemical element F1 may represent Cu, Ni and Co mineralization of mafic-ultramafic rocks. There are 607 samples with the factor F1 scores higher than 2 among all the 3806 samples from Pingran area. Distribution characteristics of the factor F1 score anoma-lies are roughly consistent with those of Au,As and Cu anomalies in Pingran area. Thus,the overlapped portion between the Cu, Ni and Co anomaly area and the area where factor F1 scores are higher than 2 should be the key ore-prospecting target dominated by Cu, Ni and Co.%1∶5万水系沉积物测量显示,平然地区矿化异常是一个以Cu、Ni、Co异常为主,伴随有Cr、V、Ti等的

  20. Geochemical research of soil and attic dust in Litija area, Slovenia

    Directory of Open Access Journals (Sweden)

    Mateja Jemec


    Full Text Available Geochemical research was carried as part of the environmental research project at the Geological Survey of Slovenia. The aim of the project was to determine the impact on the environment caused by heavy metals released in the environment during mining and smeltingactivity in the area of Litija. The samples of attic dust and soil (0–5 cm were examined with the view to separate the natural distribution of chemical elements in the environment from the one caused by past mining and smelting activities. Based on chemically analyses we determine two main geochemical associations and their spatial distribution. First geochemical association (Al, Co, Ce, K, La, Li, Nb, Rb, Sc, Ta, Th in Ti is influencedmainlybynatural source, the second man-made association (As, Cd, Hg, Pb, Sb, Sn in Zn is caused mainly because of mining and lead smelting.

  1. Geochemical maps of stream sediments in central Colorado, from New Mexico to Wyoming (United States)

    Eppinger, Robert G.; Giles, Stuart A.; Klein, Terry L.


    The U.S. Geological Survey has completed a series of geologic, mineral resource, and environmental assessment studies in the Rocky Mountains of central Colorado, from Leadville eastward to the range front and from New Mexico to the Wyoming border. Regional stream-sediment geochemical maps, useful for assessing mineral resources and environmental effects of historical mining activities, were produced as part of the study. The data portrayed in this 56-parameter portfolio of landscape geochemical maps serve as a geochemical baseline for the region, indicate element abundances characteristic of various lithologic terranes, and identify gross anthropogenic effects of historical mining. However, although reanalyzed in this study by modern, sensitive methods, the majority of the stream-sediment samples were collected in the 1970s. Thus, metal concentrations portrayed in these maps represent stream-sediment geochemistry at the time of collection.

  2. Geochemical Mapping——Evolution of Its Aims, Ideas and Technology

    Institute of Scientific and Technical Information of China (English)

    XIE Xuejing


    The development of geochemical mapping progressed from local geochemical prospecting through regional geochemical exploration and regional geochemical mapping to national and global geochemical mapping. This paper discusses the evolution of aims, ideas and methodology of geochemical mapping in Western countries, Russia and China. The sophistication of geochemical mapping methodology will make great contributions to solving resources and environmental problems in the 21st century.

  3. The effects of physical and geochemical heterogeneities on hydro-geochemical transport and effective reaction rates. (United States)

    Atchley, Adam L; Navarre-Sitchler, Alexis K; Maxwell, Reed M


    The role of coupled physical and geochemical heterogeneities in hydro-geochemical transport is investigated by simulating three-dimensional transport in a heterogeneous system with kinetic mineral reactions. Ensembles of 100 physically heterogeneous realizations were simulated for three geochemical conditions: 1) spatially homogeneous reactive mineral surface area, 2) reactive surface area positively correlated to hydraulic heterogeneity, and 3) reactive surface area negatively correlated to hydraulic heterogeneity. Groundwater chemistry and the corresponding effective reaction rates were calculated at three transverse planes to quantify differences in plume evolution due to heterogeneity in mineral reaction rates and solute residence time (τ). The model is based on a hypothetical CO2 intrusion into groundwater from a carbon capture utilization and storage (CCUS) operation where CO2 dissolution and formation of carbonic acid created geochemical dis-equilibrium between fluids and the mineral galena that resulted in increased aqueous lead (Pb(2+)) concentrations. Calcite dissolution buffered the pH change and created conditions of galena oversaturation, which then reduced lead concentrations along the flow path. Near the leak kinetic geochemical reactions control the release of solutes into the fluid, but further along the flow path mineral solubility controls solute concentrations. Simulation results demonstrate the impact of heterogeneous distribution of geochemical reactive surface area in coordination with physical heterogeneity on the effective reaction rate (Krxn,eff) and Pb(2+) concentrations within the plume. Dissimilarities between ensemble Pb(2+) concentration and Krxn,eff are attributed to how geochemical heterogeneity affects the time (τeq) and therefore advection distance (Leq) required for the system to re-establish geochemical equilibrium. Only after geochemical equilibrium is re-established, Krxn,eff and Pb(2+) concentrations are the same for all

  4. Gas Hydrate Exploration, Mid Chilean Coast; Geochemical-Geophysical Survey (United States)


    1986. Observaciones biológicas sobre invertebrados demersales de la zona central de Chile. In: P. Arana (ed.). La pesca en Chile: 51-56. CH4/g wet sed (ppbw) C2H6 (nM) ng C2H6/g wet sed (ppbw) C1/C2 (vol) C1/C2 (mass) SMI (cm) 1 7 544.0 19284 27.1 0.00 3.5...mM) δ13C DIC Gas Sample Depth Below Surface (cm) CH4 (mM) ng CH4/g wet sed (ppbw) C2H6 (nM) ng C2H6/g wet sed (ppbw) C1/C2 (vol

  5. A Geochemical Survey of Groundwater in Khana and Gokana Local ...

    African Journals Online (AJOL)

    Akata Formation consists oi' low density, high-pressure possibly deep marine ... the escape of dissolved gases. .... Free Carbon dioxide (CO2) resulting from gas flaring in the area ... Total Dissolved Solids (TDS) range in value from. 0.00lmg/l ...

  6. Geochemical mapping of New Mexico, USA, using stream sediment data (United States)

    Zumlot, Taisser; Goodell, Philip; Howari, Fares


    The spatial analysis of geochemical data has several environmental and geological applications. The present study investigated the regional distribution of Al, Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Ni, Pb, Sc, Th, Ti, U, V, and Zn elements in stream sediment samples from New Mexico State. These elements were studied in order to integrate them with geological and environmental characteristics of the area. Data are used from 27,798 samples that were originally collected during the national uranium resource evaluation (NURE) Hydrogeochemical and stream sediment reconnaissance (HSSR) program in the 1970s. The original data are available as U.S. Geological Survey Open-File Report 97-492. The study used a variety of data processing and filtering techniques that included univariate, bivariate, factor analyses and spatial analyses to transform the data into a useable format. Principal component analysis and GIS techniques are applied to classify the elements and to identify geochemical signatures, either natural or anthropogenic. The study found that the distribution of the investigated elements is mainly controlled by the bed rock chemistry. For example, along the Rio Grande rift and Jemez lineament a strong association between Co, Cr, Cu, Fe, Ni, Sc, Ti, V and Zn was observed and indicates that elements distribution in the area controlled by the mafic factor. The rare earth elements (REE) factor which is consists of Ce, La and U, also has strong, localized, clusters in the felsic centers in New Mexico.

  7. Geochemical Interactions and Viral-Prokaryote Relationships in Freshwater Environments (United States)

    Kyle, J. E.; Ferris, G.


    Viral and prokaryotic abundances were surveyed throughout southern Ontario aquatic habitats to determine relationships with geochemical parameters in the natural environment. Surface water samples were collected from acid mine drainage in summer of 2007 and 2008 and from circum-neutral pH environments in October to November 2008. Site determination was based on collecting samples from various aquatic habitats (acid mine drainage, lakes, rivers, tributaries, wetlands) with differing bedrock geology (limestone and shale dominated vs granitic Canadian Shield) to obtain a range of geochemical conditions. At each site, measurements of temperature, pH, and Eh were conducted. Samples collected for microbial counts and electron imaging were preserved to a final concentration of 2.5 % (v/v) glutaraldehyde. Additional sample were filtered into 60 mL nalgene bottles and amber EPA certified 40 mL glass vials to determine chemical constituents and dissolved organic carbon (DOC), respectively. Water was also collected to determine additional physiochemical parameters (dissolved total iron, ferric iron, nitrate, sulfate, phosphate, alkalinity, and turbidity). All samples were stored at 4 °C until analysis. Viral and prokaryotic abundance was determined by staining samples with SYBR Green I and examining with a epifluorescence microscope under blue excitation. Multiple regression analysis using stepwise backwards regression and general linear models revealed that viral abundance was the most influential predictor of prokaryotic abundance. Additional predictors include pH, sulfate, phosphate, and magnesium. The strength of the model was very strong with 90 % of the variability explained (R2 = 0.90, p multicollinearity with sulfate, iron was removed from the model (as sulfate acts more conservatively across the range of pH sampled, 2.5-9.0). Geochemical variables that have been reported to influence viral abundances under laboratory and field experiments (i.e. Ca2+, DOC

  8. Telescoping ore targets by geochemical exploration at multiple scales in Eastern Yunnan Pt geochemical province,southwestern China

    Institute of Scientific and Technical Information of China (English)


    Platinum has been one of the highly needed mineral resources in China.The geochemical exploration at two survey scales was applied in telescoping ore targets for the first time in Eastern Yunnan Pt geochemical province that was delineated using Pt data from flood plain sediments with extra-low sampling density.Our study was based on the delineations and assessments of both regional and local Pt anomalies using the Pt data by analyzing with C-OES the composite samples with two sampling densities.The composite samples were obtained by recomposing at two sampling densities the original stream sediment samples collected by the National Geochemical Mapping Project.Semivariograms were used to quantitatively describe the variability of Pt anomalies and further analyze the factors controlling the variability.Pt resource potentials of both the regional Pt anomalies and the local Pt anomalies in the study area were estimated based on the geochemical block methods,respectively.It comes to the conclusions as follows.(1) From the regional to local Pt anomaly,the factors controlling their variability from the deep seated faults-basalts turn into the basalts-branch faults,which suggest that Semivariograms could identify the geological factors controlling the variability of the Pt anomalies identified by the Pt data from the stream sediments with different sampling densities.(2) There exist two types of Pt anomalies in the study area.One is those displaying at sampling densities,and its average Pt concentration significantly increases with sampling density increasing.The other is getting weaker and/or disappears with sampling density increasing.This shows that TOTGEMS could gradu-ally eliminate non-ore anomalies and keep ore anomalies.(3) The average Pt concentration of the local Pt anomaly blocks delineated using Pt data from stream sediments with sampling density of one composite per 16 km2 is twice as much as that of the regional Pt anomaly blocks delineated using Pt data from

  9. Geochemical orientation for mineral exploration in the Hashemite Kingdom of Jordan (United States)

    Overstreet, W.C.; Grimes, D.J.; Seitz, J.F.


    This report is a supplement to previous accounts of geochemical exploration conducted in the Hashemite Kingdom of Jordan by the Natural Resources Authority of the Royal Government of Jordan and the U.S. Geological Survey. The field work on which this report is based was sponsored by the U.S. Agency for International Development, U.S. Department of State. Procedures used in collecting various kinds of rocks, ores, slags, eluvial and alluvial sediments, heavy-mineral concentrates, and organic materials for use as geochemical sample media are summarized, as are the laboratory procedures followed for the analysis of these sample materials by semiquantitative spectrographic, atomic absorption, fluorometric, and X-ray diffraction methods. Geochemical evaluations of the possibilities for economic mineral deposits in certain areas are presented. The results of these preliminary investigations open concepts for further use in geochemical exploration in the search for metallic mineral deposits in Jordan. Perhaps the most desirable new activity would be hydrogeochemical exploration for uranium and base metals, accompanied by interpretation of such remote-sensing data as results of airborne radiometric surveys and computer-enhanced LANDSAT imagery. For more conventional approaches to geochemical exploration, however, several fundamental problems regarding proper choice of geochemical sample media for different geologic and geographic parts of the Country must be solved before effective surveys can be made. The present results also show that such common geochemical exploration techniques as the determination of the trace-element contents of soils, plant ash, and slags have direct application also toward the resolution of several archaeological problems in Jordan. These include the relation of trace-elements chemistry of local soils to the composition of botanic remains, the trace-elements composition of slags to the technological development of the extractive metallurgy of

  10. Urban geochemical mapping : essential information for redevelopment


    Fordyce, Fiona; Ferguson, Alex; Shaw, Richard; Baldock, John


    Cost-effective fit-for-purpose redevelopment of brownfield sites requires both regional and local information on the physical and chemical states of the near-surface environment. The BGS G-BASE programme is providing baseline/benchmark geochemical data for both rural and urban areas based on the collection of stream sediment, stream water and soil samples.

  11. Metallogenetic and geochemical provinces : book review

    NARCIS (Netherlands)

    Schuiling, R.D.


    In November 1972 a symposium on metallogenetic and geochemical provinces was organized in Leoben by Prof. W.E. Petrascheck; the proceedings of this symposium have now appeared. The book is recommended to all those who want to combine their interest in economic geology with a somewhat wider

  12. Metallogenetic and geochemical provinces : book review

    NARCIS (Netherlands)

    Schuiling, R.D.


    In November 1972 a symposium on metallogenetic and geochemical provinces was organized in Leoben by Prof. W.E. Petrascheck; the proceedings of this symposium have now appeared. The book is recommended to all those who want to combine their interest in economic geology with a somewhat wider outlook i

  13. Geobiochemistry: Placing Biochemistry in Its Geochemical Context (United States)

    Shock, E.; Boyer, G. M.; Canovas, P. A., III; Prasad, A.; Dick, J. M.


    Goals of geobiochemistry include simultaneously evaluating the relative stabilities of microbial cells and minerals, and predicting how the composition of biomolecules can change in response to the progress of geochemical reactions. Recent developments in theoretical geochemistry make it possible to predict standard thermodynamic properties of proteins, nucleotides, lipids, and many metabolites including the constituents of the citric acid cycle, at all temperatures and pressures where life is known to occur, and beyond. Combining these predictions with constraints from geochemical data makes it possible to assess the relative stabilities of biomolecules. Resulting independent predictions of the environmental occurrence of homologous proteins and lipid side-chains can be compared with observations from metagenomic and metalipidomic data to quantify geochemical driving forces that shape the composition of biomolecules. In addition, the energetic costs of generating biomolecules from within a diverse range of habitable environments can be evaluated in terms of prevailing geochemical variables. Comparisons of geochemical bioenergetic calculations across habitats leads to the generalization that the availability of H2 determines the cost of autotrophic biosynthesis relative to the aquatic environment external to microbial cells, and that pH, temperature, pressure, and availability of C, N, P, and S are typically secondary. Increasingly reduced conditions, which are determined by reactions of water with mineral surfaces and mineral assemblages, allow many biosynthetic reactions to shift from costing energy to releasing energy. Protein and lipid synthesis, as well as the reverse citric acid cycle, become energy-releasing processes under these conditions. The resulting energy balances that determine habitability contrast dramatically with assumptions derived from oxic surface conditions, such as those where human biochemistry operates.

  14. Geochemical and geophysical monitoring of thermal waters in Sloveniain relation to seismic activity


    Dolenec, T.; Popit, A.; J. Vaupotic


    Pre-seismic related strains in the Earth s crust are the main cause of the observed geophysical and geochemical anomalies in ground waters preceding an earthquake. Posoc?je Region, situated along the Soc?a River, is one of the most seismically active areas of Slovenia. Our measuring stations close to the Posoc?je Region were installed in the thermal springs at Bled in 1998 and at Zatolmin in 1999. Since the beginning of our survey, radon concentration, electrical conductiv...

  15. A geochemical perspective of Red Mountain: an unmined volcanogenic massive sulfide deposit in the Alaska Range (United States)

    Giles, Stuart A.; Eppinger, Robert G.


    The U.S. Geological Survey (USGS) has investigated the environmental geochemistry of a group of unmined volcanogenic massive sulfide (VMS) deposits in the Bonnifield mining district, Alaska Range, east-central Alaska. The spectacularly colored Red Mountain deposit is the best exposed of these and provides excellent baseline geochemical data for natural environmental impacts of acidic rock drainage, metal dissolution and transport, and acidic salt and metal precipitation from an exposed and undisturbed VMS deposit.

  16. Geochemical engineering problem identification and program description. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Crane, C.H.; Kenkeremath, D.C.


    The Geochemical Engineering Program has as its goal the improvement of geochemical fluid management techniques. This document presents the strategy and status of the Geochemical Engineering Program. The magnitude and scope of geochemical-related problems constraining geothermal industry productivity are described. The goals and objectives of the DGE Geochemical Engineering Program are defined. The rationale and strategy of the program are described. The structure, priorities, funding, and management of specific elements within the program are delineated, and the status of the overall program is presented.

  17. Geochemical and mineralogical maps for soils of the conterminous United States (United States)

    Smith, David B.; Cannon, William F.; Woodruff, Laurel G.; Solano, Federico; Ellefsen, Karl J.


    The U.S. Geological Survey began sampling in 2007 for a low-density (1 site per 1,600 square kilometers, 4,857 sites) geochemical and mineralogical survey of soils in the conterminous United States as part of the North American Soil Geochemical Landscapes Project. The sampling protocol for the national-scale survey included, at each site, a sample from a depth of 0 to 5 centimeters, a composite of the soil A horizon, and a deeper sample from the soil C horizon or, if the top of the C horizon was at a depth greater than 1 meter, a sample from a depth of approximately 80–100 centimeters. The elements by methods that yield the total or near-total elemental content. The major mineralogical components in the samples from the soil A and C horizons were determined by a quantitative X-ray diffraction method using Rietveld refinement. Sampling in the conterminous United States was completed in 2010, with chemical and mineralogical analyses completed in May 2013. The resulting data set provides an estimate of the abundance and spatial distribution of chemical elements and minerals in soils of the conterminous United States and represents a baseline for soil geochemistry and mineralogy against which future changes may be recognized and quantified. This report releases geochemical and mineralogical maps along with a histogram, boxplot, and empirical cumulative distribution function plot for each element or mineral.

  18. A geochemical examination of humidity cell tests (United States)

    Maest, Ann; Nordstrom, D. Kirk


    Humidity cell tests (HCTs) are long-term (20 to >300 weeks) leach tests that are considered by some to be the among the most reliable geochemical characterization methods for estimating the leachate quality of mined materials. A number of modifications have been added to the original HCT method, but the interpretation of test results varies widely. We suggest that the HCTs represent an underutilized source of geochemical data, with a year-long test generating approximately 2500 individual chemical data points. The HCT concentration peaks and valleys can be thought of as a “chromatogram” of reactions that may occur in the field, whereby peaks in concentrations are associated with different geochemical processes, including sulfate salt dissolution, sulfide oxidation, and dissolution of rock-forming minerals, some of which can neutralize acid. Some of these reactions occur simultaneously, some do not, and geochemical modeling can be used to help distinguish the dominant processes. Our detailed examination, including speciation and inverse modeling, of HCTs from three projects with different geology and mineralization shows that rapid sulfide oxidation dominates over a limited period of time that starts between 40 and 200 weeks of testing. The applicability of laboratory tests results to predicting field leachate concentrations, loads, or rates of reaction has not been adequately demonstrated, although early flush releases and rapid sulfide oxidation rates in HCTs should have some relevance to field conditions. Knowledge of possible maximum solute concentrations is needed to design effective treatment and mitigation approaches. Early flush and maximum sulfide oxidation results from HCTs should be retained and used in environmental models. Factors that complicate the use of HCTs include: sample representation, time for microbial oxidizers to grow, sample storage before testing, geochemical reactions that add or remove constituents, and the HCT results chosen for use

  19. Geochemical dynamics in selected Yellowstone hydrothermal features (United States)

    Druschel, G.; Kamyshny, A.; Findlay, A.; Nuzzio, D.


    Yellowstone National Park has a wide diversity of thermal features, and includes springs with a range of pH conditions that significantly impact sulfur speciation. We have utilized a combination of voltammetric and spectroscopic techniques to characterize the intermediate sulfur chemistry of Cinder Pool, Evening Primrose, Ojo Caliente, Frying Pan, Azure, and Dragon thermal springs. These measurements additionally have demonstrated the geochemical dynamics inherent in these systems; significant variability in chemical speciation occur in many of these thermal features due to changes in gas supply rates, fluid discharge rates, and thermal differences that occur on second time scales. The dynamics of the geochemical settings shown may significantly impact how microorganisms interact with the sulfur forms in these systems.

  20. Seeking a geochemical identifier for authigenic carbonate. (United States)

    Zhao, Ming-Yu; Zheng, Yong-Fei; Zhao, Yan-Yan


    Authigenic carbonate was recently invoked as a third major global carbon sink in addition to primary marine carbonate and organic carbon. Distinguishing the two carbonate sinks is fundamental to our understanding of Earth's carbon cycle and its role in regulating the evolution of atmospheric oxygen. Here, using microscale geochemical measurements of carbonates in Early Triassic strata, we show that the growth of authigenic carbonate follows a different trajectory from primary marine carbonate in a cross-plot of uranium concentration and carbon isotope composition. Thus, a combination of the two geochemical variables is able to distinguish between the two carbonate sinks. The temporal distribution of authigenic carbonates in the Early Triassic strata suggests that the increase in the extent of carbonate authigenesis acted as a negative feedback to the elevated atmospheric CO2 concentration.

  1. Geochemical Investigations of Respirable Particulate Matter


    Jurinski, Joseph Bernard Jr.


    GEOCHEMICAL INVESTIGATIONS OF RESPIRABLE PARTICULATE MATTER Joseph Bernard Jurinski (Abstract) Over the course of our lives we are exposed to airborne particulate matter in the workplace, home, and environment that results in the deposition of millions of particles in the lung. These exposures may result in disease if they are significant enough. The potential for harmful exposure depends in part on the dust's biodurability and the bioavailability of harmful constituents d...

  2. Geochemical data requirements for performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Savage, D.; Stenhouse, M.J.


    This report reviews the geochemical data requirements and their application to the assessment of the performance of a geologic repository for radioactive wastes. It is concluded that information must be acquired on pH, redox reactions, inorganic and organic ligands in groundwater and colloids and processes such as precipitation, adsorption and diffusion and palaeohydrogeologic information in order to predict present hydrogeologic properties of potential repository sites. (UK).

  3. Geochemical quantification of semiarid mountain recharge. (United States)

    Wahi, Arun K; Hogan, James F; Ekwurzel, Brenda; Baillie, Matthew N; Eastoe, Christopher J


    Analysis of a typical semiarid mountain system recharge (MSR) setting demonstrates that geochemical tracers help resolve the location, rate, and seasonality of recharge as well as ground water flowpaths and residence times. MSR is defined as the recharge at the mountain front that dominates many semiarid basins plus the often-overlooked recharge through the mountain block that may be a significant ground water resource; thus, geochemical measurements that integrate signals from all flowpaths are advantageous. Ground water fluxes determined from carbon-14 ((14)C) age gradients imply MSR rates between 2 x 10(6) and 9 x 10(6) m(3)/year in the Upper San Pedro Basin, Arizona, USA. This estimated range is within an order of magnitude of, but lower than, prior independent estimates. Stable isotopic signatures indicate that MSR has a 65% +/- 25% contribution from winter precipitation and a 35% +/- 25% contribution from summer precipitation. Chloride and stable isotope results confirm that transpiration is the dominant component of evapotranspiration (ET) in the basin with typical loss of more than 90% of precipitation-less runoff to ET. Such geochemical constraints can be used to further refine hydrogeologic models in similar high-elevation relief basins and can provide practical first estimates of MSR rates for basins lacking extensive prior hydrogeologic measurements.

  4. Monitoring active volcanoes: The geochemical approach

    Directory of Open Access Journals (Sweden)

    Takeshi Ohba


    Full Text Available

    The geochemical surveillance of an active volcano aims to recognize possible signals that are related to changes in volcanic activity. Indeed, as a consequence of the magma rising inside the volcanic "plumbing system" and/or the refilling with new batches of magma, the dissolved volatiles in the magma are progressively released as a function of their relative solubilities. When approaching the surface, these fluids that are discharged during magma degassing can interact with shallow aquifers and/or can be released along the main volcano-tectonic structures. Under these conditions, the following main degassing processes represent strategic sites to be monitored.

    The main purpose of this special volume is to collect papers that cover a wide range of topics in volcanic fluid geochemistry, which include geochemical characterization and geochemical monitoring of active volcanoes using different techniques and at different sites. Moreover, part of this volume has been dedicated to the new geochemistry tools.

  5. Geochemical engineering and materials program plan

    Energy Technology Data Exchange (ETDEWEB)



    The Department of Energy (DOE) was designated as lead agency in discharging the overall legislative mandate for federal R&D to assist the private sector in developing appropriate technology for exploiting geothermal energy resources. The Geochemical Engineering and Materials (GEM) Program was conceived, as part of DOE'S overall strategy, to address specific and plant-wide problems and uncertainties in the use of materials and in geochemical engineering. This program assists industry in the conduct of long-term,high-risk R&D needed to overcome the significant technical and economic GEM-related obstacles faced by developers and potential developers of this alternative energy source. The program focuses on: (1) Increasing the knowledge about the properties of materials and their performance under geothermal energy system conditions; (2) Developing and utilizing more reliable and/or cost-effective materials than previously available; and (3) Developing a greater understanding of and control over geochemical processes during fluid production and transport, energy conversion, and waste management. As a stand-alone program and as support to other DOE geothermal technology development programs, the GEM Program contributes to the feasibility of designing and operating efficient, reliable, and safe fluid handling and energy conversion systems.

  6. Calculation of individual isotope equilibrium constants for geochemical reactions (United States)

    Thorstenson, D.C.; Parkhurst, D.L.


    Theory is derived from the work of Urey (Urey H. C. [1947] The thermodynamic properties of isotopic substances. J. Chem. Soc. 562-581) to calculate equilibrium constants commonly used in geochemical equilibrium and reaction-transport models for reactions of individual isotopic species. Urey showed that equilibrium constants of isotope exchange reactions for molecules that contain two or more atoms of the same element in equivalent positions are related to isotope fractionation factors by ?? = (Kex)1/n, where n is the number of atoms exchanged. This relation is extended to include species containing multiple isotopes, for example 13C16O18O and 1H2H18O. The equilibrium constants of the isotope exchange reactions can be expressed as ratios of individual isotope equilibrium constants for geochemical reactions. Knowledge of the equilibrium constant for the dominant isotopic species can then be used to calculate the individual isotope equilibrium constants. Individual isotope equilibrium constants are calculated for the reaction CO2g = CO2aq for all species that can be formed from 12C, 13C, 16O, and 18O; for the reaction between 12C18 O2aq and 1H218Ol; and among the various 1H, 2H, 16O, and 18O species of H2O. This is a subset of a larger number of equilibrium constants calculated elsewhere (Thorstenson D. C. and Parkhurst D. L. [2002] Calculation of individual isotope equilibrium constants for implementation in geochemical models. Water-Resources Investigation Report 02-4172. U.S. Geological Survey). Activity coefficients, activity-concentration conventions for the isotopic variants of H2O in the solvent 1H216Ol, and salt effects on isotope fractionation have been included in the derivations. The effects of nonideality are small because of the chemical similarity of different isotopic species of the same molecule or ion. The temperature dependence of the individual isotope equilibrium constants can be calculated from the temperature dependence of the fractionation

  7. Modeling Low-temperature Geochemical Processes (United States)

    Nordstrom, D. K.


    Geochemical modeling has become a popular and useful tool for a wide number of applications from research on the fundamental processes of water-rock interactions to regulatory requirements and decisions regarding permits for industrial and hazardous wastes. In low-temperature environments, generally thought of as those in the temperature range of 0-100 °C and close to atmospheric pressure (1 atm=1.01325 bar=101,325 Pa), complex hydrobiogeochemical reactions participate in an array of interconnected processes that affect us, and that, in turn, we affect. Understanding these complex processes often requires tools that are sufficiently sophisticated to portray multicomponent, multiphase chemical reactions yet transparent enough to reveal the main driving forces. Geochemical models are such tools. The major processes that they are required to model include mineral dissolution and precipitation; aqueous inorganic speciation and complexation; solute adsorption and desorption; ion exchange; oxidation-reduction; or redox; transformations; gas uptake or production; organic matter speciation and complexation; evaporation; dilution; water mixing; reaction during fluid flow; reaction involving biotic interactions; and photoreaction. These processes occur in rain, snow, fog, dry atmosphere, soils, bedrock weathering, streams, rivers, lakes, groundwaters, estuaries, brines, and diagenetic environments. Geochemical modeling attempts to understand the redistribution of elements and compounds, through anthropogenic and natural means, for a large range of scale from nanometer to global. "Aqueous geochemistry" and "environmental geochemistry" are often used interchangeably with "low-temperature geochemistry" to emphasize hydrologic or environmental objectives.Recognition of the strategy or philosophy behind the use of geochemical modeling is not often discussed or explicitly described. Plummer (1984, 1992) and Parkhurst and Plummer (1993) compare and contrast two approaches for

  8. A geomorphic-geochemical framework for quantifying the cycling of sediment-associated contaminants in fluvial systems (United States)

    Byrne, Patrick; Lopez-Tarazon, Jose; Williams, Richard


    Recent high-profile contamination events linked to extreme floods have underlined the persistent environmental risk posed by legacy metals stored in fluvial systems worldwide. While we understand that the fate of sediment-associated metals is largely determined by the dynamics of the fluvial transport system, we still lack a process-based understanding of the spatial and temporal mechanisms that affect the physical and geochemical transfer of metals through catchments. This interdisciplinary project will exploit advances in geomorphic and geochemical analyses to develop a methodological approach and conceptual framework to answer key questions related to the dynamics and timescales of metal cycling in fluvial systems. The approach will be tested in two reaches of the mining-impacted Afon Twymyn, Wales. The main objectives are: (i) quantify the physical transport of sediment and metals over a range of river flows and model sediment pathways; (ii) establish the geochemical mobility and speciation of sediment-associated metals and how this is modified through the sediment pathways. To achieve these objectives a geomorphic-geochemical combined methodology will be applied. It includes: (i) Aerial imagery that will be acquired from UAV surveys pre- and post-high flows and transformed into high-resolution DEMs using Structure-from-Motion; (ii) suspended sediment flux will be estimated indirectly by field calibration with a logging turbidimeter; (iii) 2D hydraulic and sediment transport model (Delft3D) will be used to quantify the transport of sediment and associated metals and to map the source, pathway and sink of contaminated sediment; (iv) soil and sediment samples (including suspended sediment) will be collected pre- and post-high flows for geochemical (concentration, speciation) and mineralogical (XRD, SEM) analyses; (v) finally, a geochemical model (Geochemists Workbench) will be developed to generate hypotheses that explain observed geochemical change as a function

  9. History and evaluation of national-scale geochemical data sets for the United States (United States)

    Smith, David B.; Smith, Steven M.; Horton, John D.


    Six national-scale, or near national-scale, geochemical data sets for soils or stream sediments exist for the United States. The earliest of these, here termed the ‘Shacklette’ data set, was generated by a U.S. Geological Survey (USGS) project conducted from 1961 to 1975. This project used soil collected from a depth of about 20 cm as the sampling medium at 1323 sites throughout the conterminous U.S. The National Uranium Resource Evaluation Hydrogeochemical and Stream Sediment Reconnaissance (NURE-HSSR) Program of the U.S. Department of Energy was conducted from 1975 to 1984 and collected either stream sediments, lake sediments, or soils at more than 378,000 sites in both the conterminous U.S. and Alaska. The sampled area represented about 65% of the nation. The Natural Resources Conservation Service (NRCS), from 1978 to 1982, collected samples from multiple soil horizons at sites within the major crop-growing regions of the conterminous U.S. This data set contains analyses of more than 3000 samples. The National Geochemical Survey, a USGS project conducted from 1997 to 2009, used a subset of the NURE-HSSR archival samples as its starting point and then collected primarily stream sediments, with occasional soils, in the parts of the U.S. not covered by the NURE-HSSR Program. This data set contains chemical analyses for more than 70,000 samples. The USGS, in collaboration with the Mexican Geological Survey and the Geological Survey of Canada, initiated soil sampling for the North American Soil Geochemical Landscapes Project in 2007. Sampling of three horizons or depths at more than 4800 sites in the U.S. was completed in 2010, and chemical analyses are currently ongoing. The NRCS initiated a project in the 1990s to analyze the various soil horizons from selected pedons throughout the U.S. This data set currently contains data from more than 1400 sites. This paper (1) discusses each data set in terms of its purpose, sample collection protocols, and analytical

  10. History and evaluation of national-scale geochemical data sets for the United States

    Directory of Open Access Journals (Sweden)

    David B. Smith


    Full Text Available Six national-scale, or near national-scale, geochemical data sets for soils or stream sediments exist for the United States. The earliest of these, here termed the ‘Shacklette’ data set, was generated by a U.S. Geological Survey (USGS project conducted from 1961 to 1975. This project used soil collected from a depth of about 20 cm as the sampling medium at 1323 sites throughout the conterminous U.S. The National Uranium Resource Evaluation Hydrogeochemical and Stream Sediment Reconnaissance (NURE-HSSR Program of the U.S. Department of Energy was conducted from 1975 to 1984 and collected either stream sediments, lake sediments, or soils at more than 378,000 sites in both the conterminous U.S. and Alaska. The sampled area represented about 65% of the nation. The Natural Resources Conservation Service (NRCS, from 1978 to 1982, collected samples from multiple soil horizons at sites within the major crop-growing regions of the conterminous U.S. This data set contains analyses of more than 3000 samples. The National Geochemical Survey, a USGS project conducted from 1997 to 2009, used a subset of the NURE-HSSR archival samples as its starting point and then collected primarily stream sediments, with occasional soils, in the parts of the U.S. not covered by the NURE-HSSR Program. This data set contains chemical analyses for more than 70,000 samples. The USGS, in collaboration with the Mexican Geological Survey and the Geological Survey of Canada, initiated soil sampling for the North American Soil Geochemical Landscapes Project in 2007. Sampling of three horizons or depths at more than 4800 sites in the U.S. was completed in 2010, and chemical analyses are currently ongoing. The NRCS initiated a project in the 1990s to analyze the various soil horizons from selected pedons throughout the U.S. This data set currently contains data from more than 1400 sites. This paper (1 discusses each data set in terms of its purpose, sample collection protocols

  11. Geochemical monitoring of thermal waters in Slovenia: relationships to seismic activity. (United States)

    Zmazek, B; Italiano, F; Zivcić, M; Vaupotic, J; Kobal, I; Martinelli, G


    Thermally anomalous fluids released in seismic areas in Slovenia were the subjects of geochemical monitoring. Thermal waters were surveyed from the seismically active area of Posocje (Bled and Zatolmin; NW Slovenia) and from Rogaska Slatina in eastern Slovenia. Continuous monitoring of geochemical parameters (radon concentration, electrical conductivity, and water temperature) was performed with discrete gas sampling for their (3)He/(4)He ratio. The observed values were correlated with meteorological parameters (rainfall, barometric pressure and air temperature) and with seismic activity. Only a few earthquakes occurred in the vicinity of the measuring sites during the monitoring period. Nevertheless, changes in radon concentration, water temperature, electrical conductivity and helium isotopic ratio were detected at the three thermal springs in the periods preceding the earthquakes. A close correlation was also observed of both water temperature and electrical conductivity with the Earth tide, making the observations in the selected sites a promising tool for addressing the widely debated question of earthquake prediction.

  12. Geochemical patterns in the soils of Cyprus. (United States)

    Cohen, David R; Rutherford, Neil F; Morisseau, Eleni; Zissimos, Andreas M


    The soil geochemical atlas of Cyprus is a recent addition to the series of national to continental-scale geochemical mapping programmes implemented over the last two decades for environmental and resource applications. The study has been conducted at the high sampling density of 1 site per 1km(2), with multi-element and multi-method analysis performed on samples of top soil (0-25cm) and sub soil (50-75cm) from a grid of over 5350 sites across a major portion of Cyprus. Major and most trace elements display sharp concentration changes across the main geological boundaries but a high degree of spatial continuity and consistency of values within those boundaries. Some elements display one to two orders of magnitude difference in median concentrations between the soils developed over ultramafic or mafic units and those developed over sedimentary rocks or alluvial units. The ratio of aqua regia-extractable to total metal contents provides an indication of the general mineralogical host for a number of trace elements. The majority of soils are near-neutral to alkaline with the small proportion of areas with soil pHgeochemical values. Where the concentrations of some elements (including Pb, Hg and Sn) are indicative of contamination, the values are typically higher in the top soil samples in these areas. Variations in the concentration of elements with strong redox controls on mobility are linked to changes in sedimentary environment between deep and shallow marine conditions. Some element patterns can be related to the effects of urbanisation and sulphide mining operations; however the dominant control on soil geochemistry is the parent geology and regolith forming processes. The atlas demonstrates the effectiveness of high-density sampling in mapping local to regional-scale features of the geochemical landscape.

  13. Kriging - a challenge in geochemical mapping (United States)

    Stojdl, Jiri; Matys Grygar, Tomas; Elznicova, Jitka; Popelka, Jan; Vachova, Tatina; Hosek, Michal


    Geochemists can easily provide datasets for contamination mapping thanks to recent advances in geographical information systems (GIS) and portable chemical-analytical instrumentation. Kriging is commonly used to visualise the results of such mapping. It is understandable, as kriging is a well-established method of spatial interpolation. It was created in 1950's for geochemical data processing to estimate the most likely distribution of gold based on samples from a few boreholes. However, kriging is based on the assumption of continuous spatial distribution of numeric data that is not realistic in environmental geochemistry. The use of kriging is correct when the data density is sufficient with respect to heterogeneity of the spatial distribution of the geochemical parameters. However, if anomalous geochemical values are focused in hotspots of which boundaries are insufficiently densely sampled, kriging could provide misleading maps with the real contours of hotspots blurred by data smoothing and levelling out individual (isolated) but relevant anomalous values. The data smoothing can thus it results in underestimation of geochemical extremes, which may in fact be of the greatest importance in mapping projects. In our study we characterised hotspots of contamination by uranium and zinc in the floodplain of the Ploučnice River. The first objective of our study was to compare three methods of sampling: random (based on stochastic generation of sampling points), systematic (square grid) and judgemental sampling (based on judgement stemming from principles of fluvial deposition) as the basis for pollution maps. The first detected problem in production of the maps was the reduction of the smoothing effect of kriging using appropriate function of empirical semivariogram and setting the variation of at microscales smaller than the sampling distances to minimum (the "nugget" parameter of semivariogram). Exact interpolators such as Inverse Distance Weighting (IDW) or Radial

  14. A New Geochemical Classification of Elements

    Institute of Scientific and Technical Information of China (English)

    Qi Changmou; L. Lynn Chyi


    The geochemical classification proposed by Goldschmidt was based on meteoritic analysis and elemental partition in blast furnace. There are many surprises when applied to the discussion of natural occurrences. A modified classification of elements based on basic chemical properties and their occurrences. A modified classification of elements based on basic chemical properties and their occurrences in nature is, therefore, proposed for students learning geochemistry and geologists working in the field. Elements are classified into six groups including lithophile, oxyphile, siderophile, chalcophile, biophile, and atmophile elements. Five terms are taken from Goldshcmidt's original classification. Oxyphile is a new term.

  15. Geochemical Characterization of the Upper and Middle Floridan Aquifer System, South Florida (United States)

    Mirecki, J.; Richardson, E.; Bennett, M.; Hendel, J.


    Our study focus is to characterize the water quality and geochemical environment of the Floridan Aquifer System (FAS) throughout the regional flowpath. A synoptic survey of 21 wells (n=15, upper FAS; n=6 middle FAS) was supplemented by additional samples (n=11) obtained during exploratory well development at 4 aquifer storage recovery (ASR) pilot sites. Synoptic survey samples were analyzed intensively, yielding a dataset that consists of major and trace dissolved constituents (including metals), stable isotopes (δ18O, δ13C, δD, δ34S in sulfate and sulfide), carbon species (carbonate alkalinity and organic carbon), uranium-series radionuclides, nutrients, and selected microbes and pathogens. The objectives of this study are three-fold: 1) to provide baseline water-quality and geochemical information prior to initiation of ASR activities that are part of the Comprehensive Everglades Restoration Plan; 2) to quantify the major controls on geochemical evolution along upper and middle FAS flowpaths using geochemical modeling methods; and 3) to identify areas where water- quality may limit the feasibility of ASR methods in the FAS. Preliminary interpretations water quality changes along the regional FAS flowpath can be summarized as follows. Concentrations of dissolved constituents increase from north to south along the flow path; generally, the upper FAS has lower total dissolved solids than the middle FAS at locations where well pairs were analyzed. The redox environment changes from oxic to strongly anoxic, very close to the recharge area. Redox measurements, dissolved iron, sulfide, and sulfur isotope data are consistent with sulfate-reducing conditions. Uranium-series isotope concentrations and activities generally are below regulatory criteria, with few exceptions in both the upper and middle FAS. Areas with greater radionuclide activity occur primarily at distal flowpath locations or at the coast.

  16. The geochemical atlas of Italian soils (United States)

    De Vivo, Benedetto; Cicchella, Domenico; Albanese, Stefano; Dinelli, Enrico; Giaccio, Lucia; Lima, Annamaria; Valera, Paolo


    The geochemical Atlas of Italian agricultural and grazing land soils was carried out as part of GEMAS project whose objective was to characterize soils of rural areas of the whole Europe. Soil samples were collected at an average sampling density of 1 site per 2500 km2. Two different sample types were collected: (1) 121 agricultural soils (Ap) on regularly ploughed land to a depth of 20 cm and (2) 121 grazing land soils (Gr) (land under permanent grass cover) to a depth of 10 cm. All soil samples were air dried, sieved to pH, TOC, total carbon and total sulphur, LOI, CEC, Sr-isotopes, Pb-isotopes, MIR-spectra. By means of a GIS software, georeferenced data of the Italian territory were used to produce the geochemical maps of all the analysed elements for both agricultural and grazing land soils. Specifically, for each element and sampling media a map reporting interpolated data and graduated dots was produced; univariate statistics and graphs were also associated to each map. The Atlas also contain: 5 maps for regional variability of factor scores of elemental associations resulting from R-mode factor analysis and 15 baseline and land use maps for some selected elements (As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn, Tl, V, Zn) following the Italian intervention criteria.

  17. Geochemical baseline data, Youngs Bay, Oregon, 1974

    Energy Technology Data Exchange (ETDEWEB)

    McMechan, K.J. (ed.); Johnson, V.G.; Cutshall, N.H.


    This report comprises one part of a final report to the Alumax Pacific Aluminum Corporation on the Physical, Chemical and Biological Studies of Youngs Bay''. The data reported herein are the product of the geochemical baseline section of the project. The primary objectives of the geochemical study were: to provide a baseline record of fluoride and selected trace metal levels in Youngs Bay bottom sediment, to identify areas that might function as heavy metal traps, to attempt to determine the recent depositional history of sediment in the bay. In addition to these primary objectives, a number of secondary tasks were undertaken during the study. While time did not allow these additional studies to be carried to completion, preliminary results are included herein because of their potential usefulness in assessing the impact of environmental releases of fluoride to aquatic systems in the vicinity of Youngs Bay or elsewhere. This report is made up of two major sections. In the first, a description of sample collection and analytical procedures is followed by a discussion of the baseline results. Obvious vertical and horizontal patterns of elemental distribution are identified and their origins considered. Problems needed further research are also discussed. In the second section, the data are presented in interpretive, graphical form, as well as in tables. 35 refs., 29 figs., 14 tabs.

  18. Is formamide a geochemically plausible prebiotic solvent? (United States)

    Bada, Jeffrey L; Chalmers, John H; Cleaves, H James


    From a geochemical perspective, significant amounts of pure formamide (HCONH2) would have likely been rare on the early Earth. There may have been mixed formamide-water solutions, but even in the presence of catalyst, solutions with >20 weight% water in formamide would not have produced significant amounts of prebiotic compounds. It might be feasible to produce relatively pure formamide by a rare occurrence of freezing formamide/water mixtures at temperatures lower than formamide's freezing point (2.55 °C) but greater than the freezing point of water. Because of the high density of formamide ice it would have sunk and accumulated at the bottom of the solution. If the remaining water froze on the surface of this ice, and was then removed by a sublimation-ablation process, a small amount of pure formamide ice might have been produced. In addition a recent report suggested that ∼85 weight% formamide could be prepared by a geochemical type of fractional distillation process, offering another possible route for prebiotic formamide production.

  19. Radio-geochemical methods at surface expiotation of oil and gas fields


    Sobolev, I. S.


    A review of the situation with radio-geochemical methods of searching oil and gas fields is presented. Potential reasons of radio-geochemical anomalies formation are considered, some approaches to interpretation of radio-geochemical datum are listed

  20. Geochemical Evidence for a Terrestrial Magma Ocean (United States)

    Agee, Carl B.


    The aftermath of phase separation and crystal-liquid fractionation in a magma ocean should leave a planet geochemically differentiated. Subsequent convective and other mixing processes may operate over time to obscure geochemical evidence of magma ocean differentiation. On the other hand, core formation is probably the most permanent, irreversible part of planetary differentiation. Hence the geochemical traces of core separation should be the most distinct remnants left behind in the mantle and crust, In the case of the Earth, core formation apparently coincided with a magma ocean that extended to a depth of approximately 1000 km. Evidence for this is found in high pressure element partitioning behavior of Ni and Co between liquid silicate and liquid iron alloy, and with the Ni-Co ratio and the abundance of Ni and Co in the Earth's upper mantle. A terrestrial magma ocean with a depth of 1000 km will solidify from the bottom up and first crystallize in the perovskite stability field. The largest effect of perovskite fractionation on major element distribution is to decrease the Si-Mg ratio in the silicate liquid and increase the Si-Mg ratio in the crystalline cumulate. Therefore, if a magma ocean with perovskite fractionation existed, then one could expect to observe an upper mantle with a lower than chondritic Si-Mg ratio. This is indeed observed in modern upper mantle peridotites. Although more experimental work is needed to fully understand the high-pressure behavior of trace element partitioning, it is likely that Hf is more compatible than Lu in perovskite-silicate liquid pairs. Thus, perovskite fractionation produces a molten mantle with a higher than chondritic Lu-Hf ratio. Arndt and Blichert-Toft measured Hf isotope compositions of Barberton komatiites that seem to require a source region with a long-lived, high Lu-Hf ratio. It is plausible that that these Barberton komatiites were generated within the majorite stability field by remelting a perovskite

  1. Modeling Background Radiation in our Environment Using Geochemical Data

    Energy Technology Data Exchange (ETDEWEB)

    Malchow, Russell L.; Marsac, Kara [University of Nevada, Las Vegas; Burnley, Pamela [University of Nevada, Las Vegas; Hausrath, Elisabeth [Uniiversity of Nevada, Las Vegas; Haber, Daniel [University of Nevada, Las Vegas; Adcock, Christopher [University of Nevada, Las Vegas


    Radiation occurs naturally in bedrock and soil. Gamma rays are released from the decay of the radioactive isotopes K, U, and Th. Gamma rays observed at the surface come from the first 30 cm of rock and soil. The energy of gamma rays is specific to each isotope, allowing identification. For this research, data was collected from national databases, private companies, scientific literature, and field work. Data points were then evaluated for self-consistency. A model was created by converting concentrations of U, K, and Th for each rock and soil unit into a ground exposure rate using the following equation: D=1.32 K+ 0.548 U+ 0.272 Th. The first objective of this research was to compare the original Aerial Measurement System gamma ray survey to results produced by the model. The second objective was to improve the method and learn the constraints of the model. Future work will include sample data analysis from field work with a goal of improving the geochemical model.

  2. Geochemical and geophysical monitoring of thermal waters in Sloveniain relation to seismic activity

    Directory of Open Access Journals (Sweden)

    T. Dolenec


    Full Text Available Pre-seismic related strains in the Earth s crust are the main cause of the observed geophysical and geochemical anomalies in ground waters preceding an earthquake. Posoc?je Region, situated along the Soc?a River, is one of the most seismically active areas of Slovenia. Our measuring stations close to the Posoc?je Region were installed in the thermal springs at Bled in 1998 and at Zatolmin in 1999. Since the beginning of our survey, radon concentration, electrical conductivity and water temperature have been measured continuously once every hour. In May 2002, the number of geochemical parameters monitored was extended to ionic concentration, pH and Eh, which are analysed once a month. Before seeking a correlation between geochemical and geophysical anomalies with seismic events, the influence of meteorological (atmospheric precipitation, barometric pressure and hydrological (water table of the Tolminka River factors on observed anomalies were studied. Results at Zatolmin showed that some radon variation during the period from June to October 2002 may be related to seismic activity and not only to meteorological effects.

  3. Manual hierarchical clustering of regional geochemical data using a Bayesian finite mixture model (United States)

    Ellefsen, Karl J.; Smith, David


    Interpretation of regional scale, multivariate geochemical data is aided by a statistical technique called “clustering.” We investigate a particular clustering procedure by applying it to geochemical data collected in the State of Colorado, United States of America. The clustering procedure partitions the field samples for the entire survey area into two clusters. The field samples in each cluster are partitioned again to create two subclusters, and so on. This manual procedure generates a hierarchy of clusters, and the different levels of the hierarchy show geochemical and geological processes occurring at different spatial scales. Although there are many different clustering methods, we use Bayesian finite mixture modeling with two probability distributions, which yields two clusters. The model parameters are estimated with Hamiltonian Monte Carlo sampling of the posterior probability density function, which usually has multiple modes. Each mode has its own set of model parameters; each set is checked to ensure that it is consistent both with the data and with independent geologic knowledge. The set of model parameters that is most consistent with the independent geologic knowledge is selected for detailed interpretation and partitioning of the field samples.

  4. Bacterial communities associated with subsurface geochemical processes in continental serpentinite springs. (United States)

    Brazelton, William J; Morrill, Penny L; Szponar, Natalie; Schrenk, Matthew O


    Reactions associated with the geochemical process of serpentinization can generate copious quantities of hydrogen and low-molecular-weight organic carbon compounds, which may provide energy and nutrients to sustain subsurface microbial communities independently of the photosynthetically supported surface biosphere. Previous microbial ecology studies have tested this hypothesis in deep sea hydrothermal vents, such as the Lost City hydrothermal field. This study applied similar methods, including molecular fingerprinting and tag sequencing of the 16S rRNA gene, to ultrabasic continental springs emanating from serpentinizing ultramafic rocks. These molecular surveys were linked with geochemical measurements of the fluids in an interdisciplinary approach designed to distinguish potential subsurface organisms from those derived from surface habitats. The betaproteobacterial genus Hydrogenophaga was identified as a likely inhabitant of transition zones where hydrogen-enriched subsurface fluids mix with oxygenated surface water. The Firmicutes genus Erysipelothrix was most strongly correlated with geochemical factors indicative of subsurface fluids and was identified as the most likely inhabitant of a serpentinization-powered subsurface biosphere. Both of these taxa have been identified in multiple hydrogen-enriched subsurface habitats worldwide, and the results of this study contribute to an emerging biogeographic pattern in which Betaproteobacteria occur in near-surface mixing zones and Firmicutes are present in deeper, anoxic subsurface habitats.

  5. Advances in geochemical research on nanometer materials

    Institute of Scientific and Technical Information of China (English)


    Important advances have been made in the field of geochemistry since nanometer science and technology were introduced into the field of geoscience. The nanometer particulates have been discovered in naturally-occurring ore deposits, volcano-eruptive materials and geo-gases, and a more detailed exploration of the metallogenic mechanism of endogenic metallic ore deposits has been conducted. It is considered that some ore-forming metals may transport in the form of native particulates. Because they have very strong capabilities of adsorption, adsorption is always regarded as an important mechanism of metallogenesis under supergenic and low temperature conditions.Therefore, a new technology of ore exploration has also been developed. This paper attempts to review the new advances in geochemical research on nanometer materials, as well as its perspectivess.

  6. Geochemical Stratigraphy of Southern Parana' Lava Piles (United States)

    Marzoli, A.; De Min, A.; Marques, L. S.; Nardy, A.; Chiaradia, M.


    Basaltic lava flows of the Paranà Large Igneous Province exhibit significant regional and stratigraphic geochemical variations. While the most notable difference concerns the dominance of low-Ti (TiO2 Esmeralda low-Ti basalts (these latter being present both towards the base and the top of the sequence) in Paranà State, while in Santa Caterina State Gramado flows are interlayered with Urubici-type high-Ti basalts. The interlayering of distinct basaltic magma type requires near-synchronous eruption of chemically strongly different magma types generated from clearly heterogeneous mantle sources and erupted through separated magma plumbing systems, without apparent interaction (mixing) among the distinct basalts. In conclusion, the relative timing of low- and high-Ti magma types seems to be much more complicated than previously thought, as for example Esmeralda or Pitanga basalts, previously considered as quite late and postdating Gramado basalts, are indeed synchronous with them.

  7. Mechanisms and Geochemical Models of Core Formation

    CERN Document Server

    Rubie, David C


    The formation of the Earth's core is a consequence of planetary accretion and processes in the Earth's interior. The mechanical process of planetary differentiation is likely to occur in large, if not global, magma oceans created by the collisions of planetary embryos. Metal-silicate segregation in magma oceans occurs rapidly and efficiently unlike grain scale percolation according to laboratory experiments and calculations. Geochemical models of the core formation process as planetary accretion proceeds are becoming increasingly realistic. Single stage and continuous core formation models have evolved into multi-stage models that are couple to the output of dynamical models of the giant impact phase of planet formation. The models that are most successful in matching the chemical composition of the Earth's mantle, based on experimentally-derived element partition coefficients, show that the temperature and pressure of metal-silicate equilibration must increase as a function of time and mass accreted and so m...

  8. The geochemical record in rock glaciers (United States)

    Steig, E.J.; Fitzpatrick, J.J.; Potter, N.; Clark, D.H.


    A 9.5 m ice core was extracted from beneath the surficial debris cover of a rock glacier at Galena Creek, northwestern Wyoming. The core contains clean, bubble-rich ice with silty debris layers spaced at roughly 20 cm intervals. The debris layers are similar in appearance to those in typical alpine glaciers, reflecting concentration of debris by melting at the surface during the summer ablation season. Profiles of stable isotope concentrations and electrical conductivity measurements provide independent evidence for melting in association with debris layers. These observations are consistent with a glacial origin for the ice, substantiating the glacigenic model for rock glacier formation. The deuterium excess profile in the ice indicates that the total depth of meltwater infiltration is less than the thickness of one annual layer, suggesting that isotope values and other geochemical signatures are preserved at annual resolution. This finding demonstrates the potential for obtaining useful paleoclimate information from rock glacier ice.

  9. Geochemical and mineralogical data for soils of the conterminous United States (United States)

    Smith, David B.; Cannon, William F.; Woodruff, Laurel G.; Solano, Federico; Kilburn, James E.; Fey, David L.


    In 2007, the U.S. Geological Survey initiated a low-density (1 site per 1,600 square kilometers, 4,857 sites) geochemical and mineralogical survey of soils of the conterminous United States as part of the North American Soil Geochemical Landscapes Project. Sampling and analytical protocols were developed at a workshop in 2003, and pilot studies were conducted from 2004 to 2007 to test and refine these recommended protocols. The final sampling protocol for the national-scale survey included, at each site, a sample from a depth of 0 to 5 centimeters, a composite of the soil A horizon, and a deeper sample from the soil C horizon or, if the top of the C horizon was at a depth greater than 1 meter, from a depth of approximately 80–100 centimeters. The elements by methods that yield the total or near-total elemental content. The major mineralogical components in the samples from the soil A and C horizons were determined by a quantitative X-ray diffraction method using Rietveld refinement. Sampling in the conterminous United States was completed in 2010, with chemical and mineralogical analyses completed in May 2013. The resulting dataset provides an estimate of the abundance and spatial distribution of chemical elements and minerals in soils of the conterminous United States and represents a baseline for soil geochemistry and mineralogy against which future changes may be recognized and quantified. This report (1) describes the sampling, sample preparation, and analytical methods used; (2) gives details of the quality control protocols used to monitor the quality of chemical and mineralogical analyses over approximately six years; and (3) makes available the soil geochemical and mineralogical data in downloadable tables.

  10. Geochemical map of the Arnold Mesa Roadless Area, Yavapai County, Arizona (United States)

    Wolfe, Edward W.


    The Wilderness Act (Public Law 88-577, September 3, 1964) and related acts require the U.S. Geological Survey and the U.S. Bureau of Mines to survey certain areas on Federal lands to determine their mineral resource potential. Results must be made available to the public and be submitted to the President and the Congress. This report presents the results of a geochemical survey of the Arnold Mesa Roadless Area (U.S. Forest Service number 03092) in the Prescott and Tonto National Forests, Yavapai County, Arizona. The Arnold Mesa Roadless Area was classified as a further planning area during the Second Roadless Area Review and Evaluation (RARE II) by the U.S. Forest Service, January 1979.

  11. Integrated Geologic, Geochemical, and Geophysical Studies of Big Bend National Park, Texas (United States)

    Gray, John E.; Finn, Carol A.; Morgan, Lisa A.; Page, William R.; Shanks, Wayne C.


    Introduction Big Bend National Park (BBNP), Texas, covers 801,163 acres (3,242 km2) and was established in 1944 through a transfer of land from the State of Texas to the United States. The park is located along a 118-mi (190-km) stretch of the Rio Grande at the United States border with Mexico. The U.S. Geological Survey (USGS) began a 5-year project in 2003 with the objective of studying a number of broad and diverse geologic, geochemical, and geophysical topics in BBNP. This fact sheet describes results of some of the research by USGS scientists working in BBNP.

  12. Database creation, data quality assessment, and geochemical maps (phase V, deliverable 59)—Final report on compilation and validation of geochemical data: Chapter D in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II) (United States)

    Eppinger, Robert G.; Giles, Stuart A.; Lee, Gregory K.; Smith, Steven M.


    Under the World Bank-funded Second Projet de Renforcement Institutionnel du Secteur Minier de la Republique Islamique de Mauritanie (PRISM-II), this Phase V geochemistry report follows earlier Phase I and Phase II summary reports on geochemical data (U.S. Geological Survey, 2007 and Eppinger, 2007; respectively). All the reports are based on evaluations of geochemical data collected in 1999-2004 under an earlier World Bank program (PRISM-I) by the British Geological Survey (BGS) and the Bureau de Recherches Géologiques et Minières (BRGM) for the Government of Mauritania. There are no associated Phase III or IV reports.

  13. Geochemical evolution of groundwaterof the Iblean Foreland (Southeastern Sicily after the December 13, 1990 earthquake (M = 5.4

    Directory of Open Access Journals (Sweden)

    S. Tersigni


    Full Text Available Geochemical surveys were performed by the Istituto Nazionale di Geofisica (ING, between December 1990 and July 1991, in the framework of an interdisciplinary task study throughout the Siracusa epicentral area: these studies were aimed at col1ecting specific information on the geochemical patterns of fluids, in relation to the geodynamic and seismic evolution of the nol1hern Iblean Foreland area, stal1ing from the December, 13, 1990 Syracuse earthquake (M = 5,4. The results of the hydrogeochemical surveys, discussed in this paper, were in part unexpected. In particular, a steady decrease of the PCO2 va1ues, after the eal1hquake, in ground- waters of the epicentral area, along a NNW-SSE fault bordering the Augusta Graben (Brucoli Sulphureous Spring, was observed. This observation enabled us to reconstruct the geochemical processes triggered by the earthquake: a sudden and strong release of CO2 of deep origin, probably related to a pore pressure uprising and/or to a water/rock interaction changes in the vicinity of the seismogenic structure. The existence of deep- fluid uprising (CO2, 222Rn, NHj, H2S, as well as the variation in time of geochemica1 flows accompanying seismic activity along this NNW-SSE anomalous-sites 1ine, within the whole Iblean Foreland, witnes., the activity (as concern as fluidodynamic and geochemistry of the NNW-SSE striking Ibleo-Maltese Escarpment fault system. This fact can be taken into account in locating the seismogenic structure responsible for the 1990 earthquake, like a contribution of the geochemical methods applied to seismotectonics. During June 1992, a more complete ana1ysis of the Iblean Foreland groundwaters was performed, co1lecting data on the geochemi- ca1 feature, of the different aquifers in aseismic period. Mu1tivariable statistics, chemical equilibria studies and mapping with our geochemical data, were also performed.

  14. The IUGS/IAGC Task Group on Global Geochemical Baselines

    Institute of Scientific and Technical Information of China (English)

    David B.Smith; Shaun Reeder; Alecos Demetriades


    The Task Group on Global Geochemical Baselines,operating under the auspices of both the International Union of Geological Sciences(IUGS) and the International Association of Geochemistry(IAGC),has the long-term goal of establishing a global geochemical database to document the concentration and distribution of chemical elements in the Earth's surface or near-surface environment.The database and accompanying element distribution maps represent a geochemical baseline against which future human-induced or natural changes to the chemistry of the land surface may be recognized and quantified.In order to accomplish this long-term goal,the activities of the Task Group include:(1) developing partnerships with countries conducting broad-scale geochemical mapping studies;(2) providing consultation and training in the form of workshops and short courses;(3) organizing periodic international symposia to foster communication among the geochemical mapping community;(4) developing criteria for certifying those projects whose data are acceptable in a global geochemical database;(5) acting as a repository for data collected by those projects meeting the criteria for standardization;(6) preparing complete metadata for the certified projects;and(7) preparing,ultimately,a global geochemical database.This paper summarizes the history and accomplishments of the Task Group since its first predecessor project was established in 1988.

  15. The IUGS/IAGC Task Group on Global Geochemical Baselines (United States)

    Smith, David B.; Wang, Xueqiu; Reeder, Shaun; Demetriades, Alecos


    The Task Group on Global Geochemical Baselines, operating under the auspices of both the International Union of Geological Sciences (IUGS) and the International Association of Geochemistry (IAGC), has the long-term goal of establishing a global geochemical database to document the concentration and distribution of chemical elements in the Earth’s surface or near-surface environment. The database and accompanying element distribution maps represent a geochemical baseline against which future human-induced or natural changes to the chemistry of the land surface may be recognized and quantified. In order to accomplish this long-term goal, the activities of the Task Group include: (1) developing partnerships with countries conducting broad-scale geochemical mapping studies; (2) providing consultation and training in the form of workshops and short courses; (3) organizing periodic international symposia to foster communication among the geochemical mapping community; (4) developing criteria for certifying those projects whose data are acceptable in a global geochemical database; (5) acting as a repository for data collected by those projects meeting the criteria for standardization; (6) preparing complete metadata for the certified projects; and (7) preparing, ultimately, a global geochemical database. This paper summarizes the history and accomplishments of the Task Group since its first predecessor project was established in 1988.

  16. [Research and Application of the ICP-MS Detection Technology for the Content of Nb and Ta in Geochemical Sample]. (United States)

    Li, Zi-qiang; Li, Xiao-ying; Zhu, Kun; Xu, Xiao-xia; Yan, Zhi-yuan


    In order to provide the test analysis technology to support the exploration and development of niobium and tantalum resource, based on the special chemical properties of Nb and Ta in geochemical sample, we studied the detection methods for the content of Nb and Ta in geochemical sample by using inductively coupled plasma mass spectrometry (ICP-MS). The results show that the sample dissolution and instrumental parameter of ICP-MS, especially the former have significant influence? on detection results. Therefore, optimizing important parameters of sample dissolution is the key of the detection technology. The optimal parameters are that the weight of sample is 50 mg; the dosage of HF acid is 15 mL; the concentration of nitric acid and tartaric acid in the sample solution is 2% and 1.5%, respectively; the validity period of detection for sample solution ≤1 d. The detection method has been validated by the national geochemistry standard reference material. The precise and exaction of method meet the required of industry standards. The detection limits of method for Nb and Ta are 1.05 and 0.13 μg · g(-1), respectively. The experiment proved that the ICP-MS detection methods, which using certain preparation process of sample solutions, is suitable for accurate and rapid determination of Nb and Ta in geochemical sample, especially geochemical survey samples which with a large amount and low content of Nb and Ta.

  17. Pilot studies for the North American Soil Geochemical Landscapes Project - Site selection, sampling protocols, analytical methods, and quality control protocols (United States)

    Smith, D.B.; Woodruff, L.G.; O'Leary, R. M.; Cannon, W.F.; Garrett, R.G.; Kilburn, J.E.; Goldhaber, M.B.


    In 2004, the US Geological Survey (USGS) and the Geological Survey of Canada sampled and chemically analyzed soils along two transects across Canada and the USA in preparation for a planned soil geochemical survey of North America. This effort was a pilot study to test and refine sampling protocols, analytical methods, quality control protocols, and field logistics for the continental survey. A total of 220 sample sites were selected at approximately 40-km intervals along the two transects. The ideal sampling protocol at each site called for a sample from a depth of 0-5 cm and a composite of each of the O, A, and C horizons. The acid digestion. A separate sample of 0-5-cm material was collected at each site for determination of organic compounds. A subset of 73 of these samples was analyzed for a suite of 19 organochlorine pesticides by gas chromatography. Only three of these samples had detectable pesticide concentrations. A separate sample of A-horizon soil was collected for microbial characterization by phospholipid fatty acid analysis (PLFA), soil enzyme assays, and determination of selected human and agricultural pathogens. Collection, preservation and analysis of samples for both organic compounds and microbial characterization add a great degree of complication to the sampling and preservation protocols and a significant increase to the cost for a continental-scale survey. Both these issues must be considered carefully prior to adopting these parameters as part of the soil geochemical survey of North America.

  18. Structure-geochemical zoning of Topolninsk gold-ore field (Gorny Altai) (United States)

    Timkin, T. V.; Lavrov, D. S.; Askanakova, O. Y.; Korotchenko, T. V.


    Geochemical zoning of prospective mineable gold-bearing skarns was carried out. The geochemical field abnormal structures of different hierarchy levels associated with gold- skarn formations were revealed. The interrelation between the structure of ore-geochemical fields and associated ring structures was studied. Complex structure-geochemical criteria for gold mineralization prospecting and evaluation were proposed.

  19. The Aqueous Alteration of CR Chondrites: Experiments and Geochemical Modeling (United States)

    Perronnet, M.; Berger, G.; Zolensky, M. E.; Toplis, M. J.; Kolb, V. M.; Bajagic, M.


    Laboratory alteration experiments were performed on mineralogical assemblages having the unaltered CR composition. The mineralogy of reaction products was compared to that of Renazzo and GRO 95577 and to predictions of geochemical modeling.

  20. Identification of Sediment Sources to Calumet River through Geochemical Fingerprinting (United States)


    Other Tracers for Dredged Material Fate” ERDC TR-17-1 ii Abstract Geochemical sedimentary markers provide a well-established methodology for...12 Principal component analysis...22 Principal component analysis (PCA

  1. Chlorine isotopes potential as geo-chemical tracers

    Digital Repository Service at National Institute of Oceanography (India)

    Shirodkar, P.V.; Pradhan, U.K.; Banerjee, R.

    The potential of chlorine isotopes as tracers of geo-chemical processes of earth and the oceans is highlighted based on systematic studies carried out in understanding the chlorine isotope fractionation mechanism, its constancy in seawater and its...

  2. Investigation of Hydro-Geochemical Characteristics of Groundwater ...

    African Journals Online (AJOL)

    Investigation of Hydro-Geochemical Characteristics of Groundwater In Port Harcourt City, ... Constituents of the heavy metals as shown in this study reveal that, in some ... Microbial analysis of the water samples to determine the presumptive ...

  3. Toxicity of major geochemical ions to freshwater species (United States)

    Extensive testing regarding the toxicity of major geochemical ions to Ceriodaphnia dubia, Hyalella azteca, and Pimephales promelas will be presented. For C. dubia, tests of single salts and binary mixtures in various dilution waters demonstrated multiple mechanisms of toxicity an...

  4. Multifractal Simulation of Geochemical Map Patterns

    Institute of Scientific and Technical Information of China (English)


    Using a simple multifractal model based on the model De Wijs, various geochemical map patterns for element concentration values are being simulated. Each pattern is self-similar on the average in that a similar pattern can be derived by application of the multiplicative cascade model used to any small subarea on the pattern. In other experiments, the original, self-similar pattern is distorted by superimposing a 2-dimensional trend pattern and by mixing it with a constant concentration value model. It is investigated how such distortions change the multifractal spectrum estimated by means of the 3-step method of moments. Discrete and continuous frequency distribution models are derived for patterns that satisfy the model of De Wijs. These simulated patterns satisfy a discrete frequency distribution model that as upper bound has a continuous frequency distribution to which it approaches in form when the subdivisions of the multiplicative cascade model are repeated indefinitely. This limiting distribution is lognormal in the center and has Pareto tails. Potentially, this approach has important implications in mineral and oil resource evaluation.

  5. Geochemical Enirchment and Mineralization of Indium

    Institute of Scientific and Technical Information of China (English)

    张乾; 战新志; 等


    Indium occurs in a very dispersed manner in nature with enrichment of economic in terest rarely known.The highly dispersed nature of indium,among several other elements,has for a long time retarded our understanding of the regularities that control their mineralization,which in turn has hindered exploitation and application of these elements.Recent studies of ours show that no significant enrichment of indium can be recognized in various types of Pb-Zn sulphide deposits as well as in deposits of copper,iron and manganese,Indium Concentrations in ores of these deposits are generally below 10×10-6.In contrast,however,indium is found to be enriched to a significant extent in cassiterite-sulphide deposits and some tin-rich Pb-Zn polymetallic deposits.The average content of indium in these deposits can be over 100×10-6,and more than 90% of it is concentrated in sphalerite.Generally,these deposits may be considered as large paragenic deposits for indium and ,therefore,there must be some regularities that govern the geochemical enrichment of the so-called "dispersed element" indium.

  6. Geochemical modeling of magmatic gas scrubbing

    Directory of Open Access Journals (Sweden)

    B. Gambardella


    Full Text Available The EQ3/6 software package, version 7.2 was successfully used to model scrubbing of magmatic gas by pure water at 0.1 MPa, in the liquid and liquid-plus-gas regions. Some post-calculations were necessary to account for gas separation effects. In these post-calculations, redox potential was considered to be fixed by precipitation of crystalline a-sulfur, a ubiquitous and precocious process. As geochemical modeling is constrained by conservation of enthalpy upon water-gas mixing, the enthalpies of the gas species of interest were reviewed, adopting as reference state the liquid phase at the triple point. Our results confirm that significant emissions of highly acidic gas species (SO2(g, HCl(g, and HF(g are prevented by scrubbing, until dry conditions are established, at least locally. Nevertheless important outgassing of HCl(g can take place from acid, HCl-rich brines. Moreover, these findings support the rule of thumb which is generally used to distinguish SO2-, HCl-, and HF-bearing magmatic gases from SO2-, HCl-, and HF-free hydrothermal gases.

  7. A visual basic spreadsheet macro for geochemical background analysis. (United States)

    Nakić, Zoran; Posavec, Kristijan; Bacani, Andrea


    A Visual Basic macro entitled BACKGROUND calculates geochemical background values of chemical parameters and estimates threshold values separating background data from anomalies. The macro uses two statistical methods, the iterative 2-sigma technique and the calculated distribution function, and integrates these model-based objective methods into a widely accessible platform (i.e., MS Excel). The macro offers the possibility for automated processing of geochemical data and enables an automated generation of background range and threshold values for chemical parameters.

  8. Comparison on humus and soil geochemical baselines in Southern Finland (United States)

    Minolfi, Giulia; Tarvainen, Timo; Jarva, Jaana


    Humus has been recognized since a survey in 1977 (Allen and Steinnes, 1980) as one of the best sampling media for mapping regional environmental contamination because of the strong geochemical contrast between anomalous and background concentrations resulting from its capacity to accumulate high levels of trace metals. This study is in the framework of the comparison between humus, topsoil and moss deposition data, in order to analyze the humus behavior and to find possible similarities to underlying geology and long-range atmospheric deposition. The analyzed samples are part of a geochemical mapping programme carried out by the Geological Survey of Finland (GTK); subsoil, topsoil and humus samples have been collected in a large area in Southern Finland since 2002. 816 sample pairs (humus and topsoil samples) were selected for statistical analysis. Statistical graphs, like histograms, CP plots and box plots, were realized for 31 elements, and showed that most of the elements have completely different distribution of concentrations in humus and in topsoil samples. Then the correlation between the element concentrations in humus and minerogenic topsoil has been evaluated measuring the Spearman rank correlation value and elaborating scatter plots between the element concentrations in humus and minerogenic topsoil, and between the content of the element vs. the content of organic C. The concentrations of some elements, like K, Mg, Fe, Al, in humus samples are controlled by the content of mineral matter, derived by the soil dust. Other elements, such as As, Bi, Cd, Co, Cu, Mn, Mo, Ni, Pb, Rb, Th, V and Zn showed evident outliers, with probable anthropogenic origin. In order to explain these anomalous high values in humus, the geographic distributions of these elements in humus and topsoil were analyzed and then compared to the deposition data obtained by the national moss data. High values appear in areas where the anthropogenic impact is strong, like the Harjavalta

  9. Ternary geochemical-tracing system in natural gas accumulation

    Institute of Scientific and Technical Information of China (English)


    The establishment of geochemical-tracing system of gas generation and accumulation is helpful to re-elucidating the gas migration and accumulation in time and space. To deduce the complex process of gas accumulation, a ternary geochemical-tracing system is set up, according to stable isotope inheritance of source rocks, kinetic fractionation of stable isotopes, time-accumulating effect of noble gas isotopes, mantle-derived volatile inheritance, and organic molecule inheritance of light hydrocarbons and thermally kinetic fractionation in their generation, in combination with the previous achievements of gas geochemistry and geochemical parameters of gas-source correlation. There are tight interactions for the geochemical parameters with much information about parent inheritance and special biomarkers, in which they are confirmed each other, reciprocally associated and preferentially used for the requirement so that we can use these geochemical parameters to effectively demonstrate the sources of natural gas, sedimentary environments and thermal evolution of source rocks, migration and accumulation of natural gas, and rearrangement of natural gas reservoirs. It is necessary for the ternary geochemical-tracing system to predict the formation of high efficient gas reservoir and their distribution in time and space.

  10. Concerning evaluation of eco-geochemical background in remediation strategy (United States)

    Korobova, Elena; Romanov, Sergey


    The geochemical concept of biosphere developed by V.I. Vernadsky states the geological role of the living organisms in the course of their active chemical interaction with the inert matter (Vernadsky, 1926, 1960). Basing on this theory it is reasonable to suggest that coevolution of living organisms and their environment led to development of the dynamically stable biogeocenoses precisely adequate to their geochemical environment. Soil cover was treated by V.I. Vernadsky as a balanced bio-inert matter resulting from this interaction. Appearance of human mind and then a civilization led to global expansion of human beings, first able to survive in unfavorable geochemical conditions and then starting chemical transformation of the environment to satisfy the growing demands of mankind in food and energy. The residence in unfavorable environment and local contamination was followed by appearance of endemic diseases of plants, animals and man. Therefore zonal, regional and local chemical composition of the soil cover formed in natural conditions may be used for estimation of the optimum geochemical background, most adequate for the corresponding zonal biogeocenoses and species. Moreover, the natural geochemical background and technogenic fields have unequal spatial structure and this facilitates their identification that may be relatively easy realized in remediation strategy. On the assumption of the foregoing, the adequate methodical approach to remediation of technogenically affected areas should account of the interaction of the existing natural and the newly formed technogenic geochemical fields and include the following steps: 1) the study and mapping of geochemical structure of the natural geochemical background basing on soil maps; 2) the study of contaminants and mapping spatial distribution of technogenic releases; 3) construction of risk maps for the target risk groups with due regard to natural ecological threshold concentration in context of risk degree for

  11. Compilation of kinetic data for geochemical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, R.C. [Monitor Scientific, LLC., Denver, Colorado (United States); Savage, D. [Quintessa, Ltd., Nottingham (United Kingdom); Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan). Tokai Works


    Kinetic data, including rate constants, reaction orders and activation energies, are compiled for 34 hydrolysis reactions involving feldspars, sheet silicates, zeolites, oxides, pyroxenes and amphiboles, and for similar reactions involving calcite and pyrite. The data are compatible with a rate law consistent with surface reaction control and transition-state theory, which is incorporated in the geochemical software package EQ3/6 and GWB. Kinetic data for the reactions noted above are strictly compatible with the transition-state rate law only under far-from-equilibrium conditions. It is possible that the data are conceptually consistent with this rate law under both far-from-equilibrium and near-to-equilibrium conditions, but this should be confirmed whenever possible through analysis of original experimental results. Due to limitations in the availability of kinetic data for mine-water reactions, and in order to simplify evaluations of geochemical models of groundwater evolution, it is convenient to assume local-equilibrium in such models whenever possible. To assess whether this assumption is reasonable, a modeling approach accounting for couple fluid flow and water-rock interaction is described that can be use to estimate spatial and temporal scale of local equilibrium. The approach is demonstrated for conditions involving groundwater flow in fractures at JNC's Kamaishi in-situ tests site, and is also used to estimate the travel time necessary for oxidizing surface waters to migrate to the level of a HLW repository in crystalline rock. The question of whether local equilibrium is a reasonable assumption must be addressed using an appropriate modeling approach. To be appropriate for conditions at the Kamaishi site using the modeling approach noted above, the fracture fill must closely approximate a porous mine, groundwater flow must be purely advective and diffusion of solutes across the fracture-host rock boundary must not occur. Moreover, the

  12. Development of thermodynamic databases for geochemical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, R.C. [Monitor Scientific, L.L.C., Denver, Colorado (United States); Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan); Neyama, Atsushi [Computer Software Development Corp., Tokyo (Japan)


    Two thermodynamic databases for geochemical calculations supporting research and development on geological disposal concepts for high level radioactive waste are described in this report. One, SPRONS.JNC, is compatible with thermodynamic relations comprising the SUPCRT model and software, which permits calculation of the standard molal and partial molal thermodynamic properties of minerals, gases, aqueous species and reactions from 1 to 5000 bars and 0 to 1000degC. This database includes standard molal Gibbs free energies and enthalpies of formation, standard molal entropies and volumes, and Maier-Kelly heat capacity coefficients at the reference pressure (1 bar) and temperature (25degC) for 195 minerals and 16 gases. It also includes standard partial molal Gibbs free energies and enthalpies of formation, standard partial molal entropies, and Helgeson, Kirkham and Flowers (HKF) equation-of-state coefficients at the reference pressure and temperature for 1147 inorganic and organic aqueous ions and complexes. SPRONS.JNC extends similar databases described elsewhere by incorporating new and revised data published in the peer-reviewed literature since 1991. The other database, PHREEQE.JNC, is compatible with the PHREEQE series of geochemical modeling codes. It includes equilibrium constants at 25degC and l bar for mineral-dissolution, gas-solubility, aqueous-association and oxidation-reduction reactions. Reaction enthalpies, or coefficients in an empirical log K(T) function, are also included in this database, which permits calculation of equilibrium constants between 0 and 100degC at 1 bar. All equilibrium constants, reaction enthalpies, and log K(T) coefficients in PHREEQE.JNC are calculated using SUPCRT and SPRONS.JNC, which ensures that these two databases are mutually consistent. They are also internally consistent insofar as all the data are compatible with basic thermodynamic definitions and functional relations in the SUPCRT model, and because primary

  13. Geochemical identification of projectiles in impact rocks (United States)

    Tagle, Roald; Hecht, Lutz


    The three major geochemical methods for impactor identification are evaluated with respect to their potential and limitations with regards to the precise detection and identification of meteoritic material in impactites. The identification of a projectile component in impactites can be achieved by determining certain isotopic and elemental ratios in contaminated impactites. The isotopic methods are based on Os and Cr isotopic ratios. Osmium isotopes are highly sensitive for the detection of minute amounts of extraterrestrial components of even isotopic method requires the relatively highest projectile contamination (several wt%) in order to detect an extraterrestrial component, but may allow the identification of three different groups of extraterrestrial materials, ordinary chondrites, an enstatite chondrites, and differentiated achondrites. A significant advantage of this method is its independence of the target lithology and post-impact alteration. The use of elemental ratios, including platinum group elements (PGE: Os, Ir, Ru, Pt, Rh, Pd), in combination with Ni and Cr represents a very powerful method for the detection and identification of projectiles in terrestrial and lunar impactites. For most projectile types, this method is almost independent of the target composition, especially if PGE ratios are considered. This holds true even in cases of terrestrial target lithologies with a high component of upper mantle material. The identification of the projectile is achieved by comparison of the "projectile elemental ratio" derived from the slope of the mixing line (target-projectile) with the elemental ratio in the different types of possible projectiles (e.g., chondrites). However, this requires a set of impactite samples of various degree of projectile contamination.

  14. Petroleum geochemical proxies for reservoir engineering parameters

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, B. [Petroleum Reservoir Group (PRG), Department of Geology and Geophysics, University of Calgary, 2500 University Drive NW, Calgary, Alberta (Canada); Lager, A. [NRG: School of Civil Engineering and Geosciences, Drummond Building, The University, Newcastle upon Tyne, NE1 7RU (United Kingdom); Potter, D.K.; Buckman, J.O. [Institute of Petroleum Engineering, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS (United Kingdom); Larter, S.R. [Petroleum Reservoir Group (PRG), Department of Geology and Geophysics, University of Calgary, 2500 University Drive NW, Calgary, Alberta (Canada); NRG: School of Civil Engineering and Geosciences, Drummond Building, The University, Newcastle upon Tyne, NE1 7RU (United Kingdom)


    The prediction of fluid flow behaviour in petroleum reservoirs is influenced by the physical and chemical processes active in interacting crude oil/brine/rock systems. It is usually not possible to assess these complex systems directly so proxies for molecular scale behaviour are needed. By their very nature, polar non-hydrocarbons are sensitive to fluid-rock interactions, and if properly exploited they may be utilised as proxies for describing reservoir engineering properties (e.g. wettability) that are also sensitive to fluid-rock interactions. We have identified a group of aromatic oxygen (alkylphenols and alkylfluorenones) and aromatic nitrogen (alkylcarbazoles) compounds present in petroleum that appear to respond to variations in fluid-rock properties. Here we describe the chemical and physical changes in a series of core samples obtained from North Sea reservoirs. A number of petrophysical parameters displayed strong correlations with polar non-hydrocarbon occurrence. For example, deflections in gamma ray logs in response to clay content in a coarsening upwards sandstone unit also showed similar deflections from a number of geochemical logs. A core-flood experiment was designed to monitor the chemical and physical changes during oil migration in a siltstone core. Following completion of the core-flood experiment, Environmental Scanning Electron Microscopy (ESEM) analysis of core samples indicated hydrophilic and hydrophobic surface tendencies grading throughout the core. The distributions of polar non-hydrocarbons (e.g. C{sub 0}-C{sub 3}-phenols) appear to correspond closely to the observed wettability alteration. The results confirm the potential for developing proxies for fluid-rock interactions through monitoring the surface active compounds present in the polar non-hydrocarbon fraction of petroleum. (author)

  15. Geochemical fate of arsenic in swine litter (United States)

    Quazi, S.; Makris, K.; Sarkar, D.; Datta, R.; Punamiya, P.


    Swine diet is often supplemented by organoarsenicals, such as roxarsone to treat diseases and to promote growth. Recent data reported roxarsone degradation under anaerobic conditions in poultry litter, but no such data exist for swine wastes typically stored in unprotected lagoons in concentrated animal feeding operations (CAFOs). However, serious environmental health risk may arise upon significant arsenic (As) release into solution. The problem may be exacerbated under certain environmental conditions where organoarsenicals, such as roxarsone transform into the more toxic inorganic As, posing serious health risk to the surrounding ecosystem. The objective of this study were to analyze swine wastes collected from 19 randomly selected CAFOs in the USA for As concentrations, and to determine the geochemical fate of As in the swine waste suspensions. Swine wastes were analyzed for total-recoverable, total soluble, and water-extractable As, which were measured by ICP-MS. Speciation of As was performed following a well-established hyphenated technique using HPLC- ICPMS. Swine waste suspensions differed in solids contents; thus, the particulate matters with varying As concentrations were spiked with roxarsone and incubated under dark/light and aerobic/anaerobic conditions. Findings show the prevalence of inorganic As [As(V)] in swine waste suspension solutions. Roxarsone underwent degradation to both organoarsenicals, such as p-ASA, as well as inorganic arsenate and to a number of unidentified metabolites. Roxarsone degradation kinetics was influenced by the solids content and the air conditions (anaerobic/aerobic) of the swine waste suspensions. Maximum degradation rates were observed under anaerobic conditions, in suspensions which were low in solids content. Roxarsone degradation was primarily microbially-mediated, but in certain cases abiotic degradation was also observed, which were significantly slower.

  16. Geochemical Treasure Hunt for Primary School Children (United States)

    Tesmer, Maja; Frick, Daniel; Gerrits, Ruben; des GFZ-GeoWunderWerkstatt, Schülerlabor


    How can you inspire school children for geochemistry, and scientific exploratory urge? The key is to raise their curiosity and make learning new things a hands-on experience. The Fellows of the European Marie Curie Initial Training Network IsoNose designed and established a "Geochemical Treasure Hunt" to excite children for scientific investigations. This workshop explains primary school children the research and scientific methods of isotopic geochemistry, and their use to understand processes on the Earth's surface. From obtaining 'samples', performing various experiments, the school children gather clues leading them to the hidden treasure on the Telegrafenberg (campus of the GFZ Potsdam). The course was designed for school children to learn hands-on the meaning of elements, atoms and isotopes. In small groups the children conduct experiments of simplified methods being indispensable to any isotope geochemist. However, prior to working in any laboratory environment, a security briefing is necessary. For the course, two stages were implemented; firstly the use of harmful substances and dangerous equipment was minimised, and secondly children were equipped with size-matched personal protective equipment (lab coats, gloves, and safety googles). The purification of elements prior to isotopic analysis was visualised using colour chromatography. However, instead of using delicate mass spectrometers for the isotope ratio measurements, the pupils applied flame spectroscopy to analyse their dissolved and purified mineral solutions. Depending on the specific element present, a different colour was observed in the flame. The children plotted their colours of the flame spectroscopy onto a map and by interpreting the emerging colour patterns they localized the treasure on the map. In small teams they swarmed out on the Telegrafenberg to recover the hidden treasure. The project leading to this outreach activity has received funding from the People Programme (Marie Curie

  17. Geochemical analysis of brine samples for exploration of Borate deposits in the South of Sabzevar

    Directory of Open Access Journals (Sweden)

    Mahdi Bemani


    suggested for detailed exploration (Bemani et al., 2014. Generally speaking, for considering the spatial distribution of data the fractal method could better identify the anomalies. Also, EDA is a quick and easy method to detect anomalies. Acknowledgment The authors are grateful to the Kaniran Mining Company and the south Khorasan branch of the Iranian Mining Engineering Organization for their financial support of this study. References Bemani, M., 2012. Prospecting and Exploring of Borax in the south of Sabzevar, combination of remote sensing, field surveying and geochemical studying. M.Sc. Thesis, University of Yazd, Yazd, Iran, 137 pp (in Persian with English abstract. Bemani, M., Mojtahedzadeh, S.H. and Kohsari, A.H., 2014. Investigation of geology, mineralogy and genesis of Mohammadabad-Oryan index boron (south of Sabzevar. Iranian Journal of Crystallography and Mineralogy 22(1: 173- 186 (in Persian with English abstract. Carranza, E.J.M., 2009. Geochemical Anomaly and Mineral Prospectivity Mapping in GIS. In: M. Hale (Editor, Handbook of exploration and environmental geochemistry. Elsevier, Amsterdam, pp. 51-115. Filliben, J.J. and Heckert, A., 2005. Exploratory data analysis. Engineering Statistics Handbook, Internet, National Institute of Standards and Technology, Hasanipak, A.A. and Sharafaddin, M., 2005. Exploratory Data Analysis.Tehran University press, Tehran 996 pp (in Persian.

  18. Hydrologic Regulation of Global Geochemical Cycles (United States)

    Maher, K.


    understand the processes controlling marine isotopic weathering processes, the need to integrate solute and solid transport into Earth system models, and the need to understand the role of extreme physical and temporal heterogeneities in moderating geochemical fluxes.

  19. Geochemical Mapping of 4 Vesta Begins (United States)

    Prettyman, Thomas H.; Feldman, William C.; Forni, Olivier; Joy, Steven P.; Lawrence, David J.; LeCorre, Lucille; Mafi, Joseph N.; McCord, Thomas B.; McCoy, Timothy J.; McSween, Harry Y.; Middlefehldt, David W.; Polanskey, Carol; Rayman, Marc; Raymond, Carol A.; Reddy, Vishnu; Reedy, Robert C.; Russell, Christopher T.; Titus, Timothy N.; Toplis, Mike J.


    LAMO, including GRaND s sensitivity to different elements and geochemical processes.

  20. Adjustment of geochemical background by robust multivariate statistics (United States)

    Zhou, D.


    Conventional analyses of exploration geochemical data assume that the background is a constant or slowly changing value, equivalent to a plane or a smoothly curved surface. However, it is better to regard the geochemical background as a rugged surface, varying with changes in geology and environment. This rugged surface can be estimated from observed geological, geochemical and environmental properties by using multivariate statistics. A method of background adjustment was developed and applied to groundwater and stream sediment reconnaissance data collected from the Hot Springs Quadrangle, South Dakota, as part of the National Uranium Resource Evaluation (NURE) program. Source-rock lithology appears to be a dominant factor controlling the chemical composition of groundwater or stream sediments. The most efficacious adjustment procedure is to regress uranium concentration on selected geochemical and environmental variables for each lithologic unit, and then to delineate anomalies by a common threshold set as a multiple of the standard deviation of the combined residuals. Robust versions of regression and RQ-mode principal components analysis techniques were used rather than ordinary techniques to guard against distortion caused by outliers Anomalies delineated by this background adjustment procedure correspond with uranium prospects much better than do anomalies delineated by conventional procedures. The procedure should be applicable to geochemical exploration at different scales for other metals. ?? 1985.

  1. Multielement geochemical dataset of surficial materials for the northern Great Basin (United States)

    Coombs, Mary Jane; Kotlyar, Boris B.; Ludington, Steve; Folger, Helen W.; Mossotti, Victor G.


    This report presents geochemical data generated during mineral and environmental assessments for the Bureau of Land Management in northern Nevada, northeastern California, southeastern Oregon, and southwestern Idaho, along with metadata and map representations of selected elements. The dataset presented here is a compilation of chemical analyses of over 10,200 stream-sediment and soil samples originally collected during the National Uranium Resource Evaluation's (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program of the Department of Energy and its predecessors and reanalyzed to support a series of mineral-resource assessments by the U.S. Geological Survey (USGS). The dataset also includes the analyses of additional samples collected by the USGS in 1992. The sample sites are in southeastern Oregon, southwestern Idaho, northeastern California, and, primarily, in northern Nevada. These samples were collected from 1977 to 1983, before the development of most of the present-day large-scale mining infrastructure in northern Nevada. As such, these data may serve as an important baseline for current and future geoenvironmental studies. Largely because of the very diverse analytical methods used by the NURE HSSR program, the original NURE analyses in this area yielded little useful geochemical information. The Humboldt, Malheur-Jordan-Andrews, and Winnemucca-Surprise studies were designed to provide useful geochemical data via improved analytical methods (lower detection levels and higher precision) and, in the Malheur-Jordan-Andrews and Winnemucca Surprise areas, to collect additional stream-sediment samples to increase sampling coverage. The data are provided in *.xls (Microsoft Excel) and *.csv (comma-separated-value) format. We also present graphically 35 elements, interpolated ("gridded") in a geographic information system (GIS) and overlain by major geologic trends, so that users may view the variation in elemental concentrations over the

  2. Geochemical and GIS study of the Zarshuran Gold mine in Iran (United States)

    Sedighi, Tahereh; Sedighi, Ahmad


    Geochemical and GIS study of the Zarshuran Gold mine in Iran Sedighi Tahere 1 Sedighi Ahmad 2 (1) Geological survey of Iran ,GIS branch (2) Shabeke Pars Enginearing Company Zarshuran Gold mine is located in the north of Takab , in West of Azarbayejan Provinc There are four Gold ore types in Zarshuran ; black gouge ,Carbonate tectonized and breccia mineralized ,Massive Jasperiod and Marble and sanded. Refractory ore off Zarshuran are Gold and co-paragenetic ore like;Arsenopyrite and Orpiment. Geographic information system (GIS) has been used to determine the Gold potential of this area. By the GIS system there are different stages with contains, Gathering of all available data, Application of the integration model and the Data processing. By mineralization and Geochemical studies it is indicated that only small fraction of free Gold (21%) is present in the cyanide-soluble salpho-arsenic compound. Major Gold distribution in orpiment, regular and Arsenian Pyrite (32%) oxides, carbonates and labile sulphides (18%) and sulphides pyrite and arsenopyrite (22%). We used several information layers of the geological layer , ore deposit layer , geochemical layer , heavy mineral layer airborn Geophysical layer and remote sensing layer . Also we used from geological maps of this area. By using of the ARCGIS software , we identified the mining potentials for Gold and finally determined the Gold mining area. In this project we used the methods of simple overlay and Fuzzy logic were used. In this presentation, the authors have outlined a strategy to take up Gold mining and refractory and undersetting of the potential for refractory Gold ores in Zarshuran area ,and these results might be used for the other similar gold mines studies.

  3. Geochemical Modeling of ILAW Lysimeter Water Extracts

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    Geochemical modeling results of water extracts from simulated immobilized low-activity waste (ILAW) glasses, placed in lysimeters for eight years suggest that the secondary phase reaction network developed using product consistency test (PCT) results at 90°C may need to be modified for field conditions. For sediment samples that had been collected from near the glass samples, the impact of glass corrosion could be readily observed based upon the pH of their water extracts. For unimpacted sediments the pH ranged from 7.88 to 8.11 with an average of 8.04. Sediments that had observable impacts from glass corrosion exhibited elevated pH values (as high as 9.97). For lysimeter sediment samples that appear to have been impacted by glass corrosion to the greatest extent, saturation indices determined for analcime, calcite, and chalcedony in the 1:1 water extracts were near equilibrium and were consistent with the secondary phase reaction network developed using PCT results at 90°C. Fe(OH)3(s) also appears to be essentially at equilibrium in extracts impacted by glass corrosion, but with a solubility product (log Ksp) that is approximately 2.13 units lower than that used in the secondary phase reaction network developed using PCT results at 90°C. The solubilities of TiO2(am) and ZrO2(am) also appear to be much lower than that assumed in the secondary phase reaction network developed using PCT results at 90°C. The extent that the solubility of TiO2(am) and ZrO2(am) were reduced relative to that assumed in the secondary phase reaction network developed using PCT results at 90°C could not be quantified because the concentrations of Ti and Zr in the extracts were below the estimated quantification limit. Gibbsite was consistently highly oversaturated in the extract while dawsonite was at or near equilibrium. This suggests that dawsonite might be a more suitable phase for the secondary phase reaction network

  4. Snowmelt induced hydrologic perturbations drive dynamic microbiological and geochemical behaviors across a shallow riparian aquifer (United States)

    Danczak, Robert; Yabusaki, Steven; Williams, Kenneth; Fang, Yilin; Hobson, Chad; Wilkins, Michael


    Shallow riparian aquifers represent hotspots of biogeochemical activity in the arid western US. While these environments provide extensive ecosystem services, little is known of how natural environmental perturbations influence subsurface microbial communities and associated biogeochemical processes. Over a six-month period we tracked the annual snowmelt-driven incursion of groundwater into the vadose zone of an aquifer adjacent to the Colorado River, leading to increased dissolved oxygen (DO) concentrations in the normally suboxic saturated zone. Strong biogeochemical heterogeneity was measured across the site, with abiotic reactions between DO and sulfide minerals driving rapid DO consumption and mobilization of redox active species in reduced aquifer regions. Conversely, extensive DO increases were detected in less reduced sediments. 16S rRNA gene surveys tracked microbial community composition within the aquifer, revealing strong correlations between increases in putative oxygen-utilizing chemolithoautotrophs and heterotrophs and rising DO concentrations. The gradual return to suboxic aquifer conditions favored increasing abundances of 16S rRNA sequences matching members of the Microgenomates (OP11) and Parcubacteria (OD1) that have been strongly implicated in fermentative processes. Microbial community stability measurements indicated that deeper aquifer locations were relatively less affected by geochemical perturbations, while communities in shallower locations exhibited the greatest change. Reactive transport modeling of the geochemical and microbiological results supported field observations, suggesting that a predictive framework can be applied to develop a greater understanding of such environments.

  5. Platinum and Palladium in Coal Rock and Geochemical Anomaly in Eastern Yunnan Province,Southwest China

    Institute of Scientific and Technical Information of China (English)

    Xia Qinglin; Zhao Pengda; Cheng Qiuming; Chen Yongqing; Zhang Shengyuan


    A series of geochemical anomalies of Pt and Pd were found in 1 358 recombined samples from a geochemical stream sediment survey in eastern Yunnan (云南) Province, China. Chemical optical emission spectroscopy, X-ray fluorescence analysis, and inductively coupled plasmas atomic emission spectrometry analyses of 22 elements and chemical compositions of 21 samples from coal-bearing strata from the Late Paleozoic, Mesozoic, and Cenozoic show Pt and Pd concentrated to some extent in coal rocks, with Pd/Pt

  6. Geochemical disturbance of soil cover in the nonferrous mining centers of the Selenga River basin. (United States)

    Timofeev, Ivan V; Kosheleva, Natalia E


    The anthropogenic geochemical transformation of soil cover in large nonferrous mining centers of the Selenga River basin was assessed. The results of the geochemical survey of 2010-2012 revealed the spatial distribution patterns and abundances of 18 hazardous heavy metals and metalloids in the soils of Erdenet (Mongolia) and Zakamensk (Buryat republic, Russian Federation). In both cities, mining activities disturbed soil cover which accumulates Mo, Cu, As, Sb, W in Erdenet and Bi, W, Cd, Be, Pb, Mo, Sb in Zakamensk. Maximum accumulation of elements in Erdenet is restricted to the industrial zone. In Zakamensk, it has spread on ½ of the territory with the degree of multielemental pollution exceeding the extremely dangerous level by 16 times. The effect of mining centers on the state of the river system is local and does not spread to the Selenga River. Downstream from Erdenet, an artificial pool intercepts heavy metal and metalloid flows of the Erdenetii-Gol River. By contrast, downstream from the tailing dumps of the Dzhida tungsten-molybdenum plant the concentrations of ore elements W and Mo and their accessories Bi and Cd in the Modonkul River exceed background values by 146, 20, 57, and 21 times, respectively, decreasing by an order of magnitude 30 km downstream.

  7. Tracking riverborne sediment and contaminants in Commencement Bay, Washington, using geochemical signatures (United States)

    Takesue, Renee K.; Conn, Kathleen E.; Dinicola, Richard S.


    Large rivers carry terrestrial sediment, contaminants, and other materials to the coastal zone where they can affect marine biogeochemical cycles and ecosystems. This U.S. Geological Survey study combined river and marine sediment geochemistry and organic contaminant analyses to identify riverborne sediment and associated contaminants at shoreline sites in Commencement Bay, Puget Sound, Washington, that could be used by adult forage fish and other marine organisms. Geochemical signatures distinguished the fine fraction (.063 millimeter, mm) of Puyallup River sediment—which originates from Mount Rainier, a Cascade volcano—from glacial fine sediment in lowland bluffs that supply sediment to beaches. In combination with activities of beryllium-7 (7Be), a short-lived radionuclide, geochemical signatures showed that winter 2013–14 sediment runoff from the Puyallup River was transported to and deposited along the north shore of Commencement Bay, then mixed downward into the sediment column. The three Commencement Bay sites at which organic contaminants were measured in surface sediment did not have measurable 7Be activities in that layer, so their contaminant assemblages were attributed to sources from previous years. Concentrations of organic contaminants (the most common of which were polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and fecal sterols) were higher in the .063-mm fraction compared to the <2-mm fraction, in winter compared to summer, in river suspended sediment compared to river bar and bank sediment, and in marine sediment compared to river sediment. The geochemical property barium/aluminum (Ba/Al) showed that the median percentage of Puyallup River derived fine surface sediment along the shoreline of Commencement Bay was 77 percent. This finding, in combination with higher concentrations of organic contaminants in marine rather than river sediment, indicates that riverborne sediment-bound contaminants are retained in shallow marine

  8. Baseline geochemical data for stream sediment and surface water samples from Panther Creek, the Middle Fork of the Salmon River, and the Main Salmon River from North Fork to Corn Creek, collected prior to the severe wildfires of 2000 in central Idaho (United States)

    Eppinger, Robert G.; Briggs, Paul H.; Brown, Zoe Ann; Crock, James G.; Meier, Allen; Theodorakos, Peter M.; Wilson, Stephen A.


    In 1996, the U.S. Geological Survey conducted a reconnaissance baseline geochemical study in central Idaho. The purpose of the baseline study was to establish a 'geochemical snapshot' of the area, as a datum for monitoring future change in the geochemical landscape, whether natural or human-induced. This report presents the methology, analytical results, and sample descriptions for water, sediment, and heavy-mineral concentrate samples collected during this geochemical investigation. In the summer of 2000, the Clear Creek, Little Pistol, and Shellrock wildfires swept across much of the area that was sampled. Thus, these data represent a pre-fire baseline geochemical dataset. A 2001 post- fire study is planned and will involve re-sampling of the pre-fire baseline sites, to allow for pre- and post-fire comparison.

  9. Geochemical Enhancement Of Enhanced Geothermal System Reservoirs: An Integrated Field And Geochemical Approach

    Energy Technology Data Exchange (ETDEWEB)

    Joseph N. Moore


    The geochemical effects of injecting fluids into geothermal reservoirs are poorly understood and may be significantly underestimated. Decreased performance of injection wells has been observed in several geothermal fields after only a few years of service, but the reasons for these declines has not been established. This study had three primary objectives: 1) determine the cause(s) of the loss of injectivity; 2) utilize these observations to constrain numerical models of water-rock interactions; and 3) develop injection strategies for mitigating and reversing the potential effects of these interactions. In this study rock samples from original and redrilled injection wells at Coso and the Salton Sea geothermal fields, CA, were used to characterize the mineral and geochemical changes that occurred as a result of injection. The study documented the presence of mineral scales and at both fields in the reservoir rocks adjacent to the injection wells. At the Salton Sea, the scales consist of alternating layers of fluorite and barite, accompanied by minor anhydrite, amorphous silica and copper arsenic sulfides. Amorphous silica and traces of calcite were deposited at Coso. The formation of silica scale at Coso provides an example of the effects of untreated (unacidified) injectate on the reservoir rocks. Scanning electron microscopy and X-ray diffractometry were used to characterize the scale deposits. The silica scale in the reservoir rocks at Coso was initially deposited as spheres of opal-A 1-2 micrometers in diameter. As the deposits matured, the spheres coalesced to form larger spheres up to 10 micrometer in diameter. Further maturation and infilling of the spaces between spheres resulted in the formation of plates and sheets that substantially reduce the original porosity and permeability of the fractures. Peripheral to the silica deposits, fluid inclusions with high water/gas ratios provide a subtle record of interactions between the injectate and reservoir rocks

  10. Salinization processes in the unconfined aquifer of Bou-Areg (NE Morocco): A geostatistical, geochemical, and tomographic study

    Energy Technology Data Exchange (ETDEWEB)

    El Yaouti, F. [Laboratory of LGA, Faculty of Sciences, University Mohammed I, Oriental Center of Water Science and Technology (COSTE), P.B. 524, Oujda (Morocco)], E-mail:; El Mandour, A. [Laboratory of Hydrogeology, Faculty of Sciences Semlalia, University Cadi Ayyad, P.B. 2390, Marrakech (Morocco)], E-mail:; Khattach, D. [Laboratory of LGA, Faculty of Sciences, University Mohammed I, Oriental Center of Water Science and Technology (COSTE), P.B. 524, Oujda (Morocco)], E-mail:; Benavente, J. [Water Research Institute, University of Granada, Ramon y Cajal, 4, 18071 Granada (Spain)], E-mail:; Kaufmann, O. [Polytechnic Faculty of Mons, Service of Fundamental and Applied Geology, Mons (Belgium)


    Hydrogeological and geochemical data, in conjunction with the results of an electrical imaging tomographic survey, were examined to determine the main factors and mechanisms controlling the groundwater chemistry and salinity of the unconfined aquifer of Bou-Areg, on the Mediterranean coast of NE Morocco. In addition, statistical and geochemical interpretation methods were used to identify the distribution of the salinity. Multivariate statistical analysis (cluster and principal component factors) revealed the main sources of contamination. Groups A, B, and C in the cluster analysis and Factors 1-3 (Factor 1: CE, Cl{sup -}, K{sup +}, SO{sub 4}{sup 2-}, and Mg{sup 2+}; Factor 2: Ca{sup 2+}, HCO{sub 3}{sup -}, and pH; Factor 3: NO{sub 3}{sup -}) represent the 'signature' of seawater intrusion in the coastal zone, the influence of marly-gypsum outcrops in the upstream zone, and anthropogenic sources, respectively. The ionic delta, the ionic ratio, the saturation index, and Stuyfzand's method were applied to evaluate geochemical processes. The results obtained indicate, on the one hand, the phenomenon of salinization in both the coastal and the upstream zones, and on the other, the dilution of groundwater by recharge. Cation exchange is shown to modify the concentration of ions in groundwater. Locally, with respect to salinization processes in the coastal zone, the results of electrical imaging tomography show that salinity increases both with depth and laterally inland from the coastline, due to seawater intrusion.

  11. Numerical modeling of geochemical variations caused by crustal relamination

    NARCIS (Netherlands)

    Vogt, Katharina; Castro, Antonio; Gerya, Taras


    Geochemical consequences of composite diapirs formed in subduction zones have been studied using a thermomechanical numerical model of an ocean-continent subduction zone. This model includes dehydration of subducted crust, aqueous fluid transport, partial melting, and melt emplacement. Subduction of

  12. Mineralogical and geochemical study of mud volcanoes in north ...

    African Journals Online (AJOL)


    Key word: Mud volcano, clay mineralogy, geochemistry, mud breccias, North Moroccan Atlantic margin. INTRODUCTION .... The geochemical analysis of the metals shows a high Ti ..... smectite evolved into an illite, or because the initial source is not .... Pinheiro LM, Kopf A, Boetius A (2006): Microbial methane turnover at.

  13. The Characteristics and Working Conditions of Several Geochemical Softwares

    Institute of Scientific and Technical Information of China (English)

    YU; Zhen-hua


    <正>During the development of geosciences and environmental science, it is difficult to give many quantitative indicators by experiment. It can be given only by means of the geochemical simulation software. So a number of research institutions and commercial companies develop a variety of such software. They have respective advantages as regards the different simulated.

  14. A Low-Li Geochemical Province in the NE Atlantic

    DEFF Research Database (Denmark)

    Bailey, J. C.; Gwozdz, R.


    Lithium was analysed in 392 basalts and related igneous rocks from the North Atlantic Tertiary-Recent province using activation analysis and Čerenkov counting. Monotonous Li values of 5.5±2 ppm in NE Atlantic basalts define a low-Li geochemical province which has persisted for 60 million years...

  15. Well sediments: a medium for geochemical prospecting, an example from the Nisa region, Portugal

    NARCIS (Netherlands)

    Vriend, S.P.; Dekkers, M.J.; Janssen, M.A.; Commandeur, J.


    Vriend, S.P., Dekkers, M.J.. Janssen, M.A. and Commandeur, J., 1991. Well sediments: a medium for geochemical prospecting, an example from the Nisa region. Portugal. In: A.W. Rose and P.M. Taufen I Editors). Geochemical Exploration ! 989. J. Geochem. Expior., 4 ! : ! 5 I- 167. Tile potential of well

  16. Geochemical Mapping: With Special Emphasis on Analytical Requirements

    Institute of Scientific and Technical Information of China (English)

    XIE Xuejing; CHENG Hangxin; LIU Dawen


    More than 40 national and regional geochemical mapping projects in the world carried out from 1973 to 1988 do not conform to common standards. In particular they have many analytical deficiencies. In the period 1988 to 1992, the International Geochemical Mapping project (Project 259 of UNESCO's IGCP Program) prepared recommendations designed to standardize geochemical mapping methods. The analytical requirements are an essential component of the overall recommendations. They included the following: 71 elements should be analyzed in future mapping projects; the detection limits of trace and ultratrace elements must be lower than the corresponding crustal abundances; and the Chinese GSD and Canadian STSD standard sample series should be used for the correlation of global data. A proposal was also made to collect 5000 composite samples, at very low sampling densities to cover the whole Earth's land surface. In 1997 an IUGS Working Group on Global Geochemical Baselines was formed to continue the work which began with IGCP 259. From 1997 up to now, new progress has been made especially in China and FOREGS countries under the aegis of this working group, including the study of suitable sampling media, development of a multi-element analytical system, new proficiency test for selection of competent laboratories and role of wide-spaced mapping in mineral exploration. One of the major problems awaiting solution has been the inability of many laboratories to meet the IGCP recommendations to generate high quality geochemical maps. Fortunately several laboratories in China and Europe have demonstrated an ability to meet the requirements and they will be well placed to render technical assistance to other countries.

  17. Validation of the WATEQ4 geochemical model for uranium

    Energy Technology Data Exchange (ETDEWEB)

    Krupka, K.M.; Jenne, E.A.; Deutsch, W.J.


    As part of the Geochemical Modeling and Nuclide/Rock/Groundwater Interactions Studies Program, a study was conducted to partially validate the WATEQ4 aqueous speciation-solubility geochemical model for uranium. The solubility controls determined with the WATEQ4 geochemical model were in excellent agreement with those laboratory studies in which the solids schoepite (UO/sub 2/(OH)/sub 2/ . H/sub 2/O), UO/sub 2/(OH)/sub 2/, and rutherfordine ((UO/sub 2/CO/sub 3/) were identified as actual solubility controls for uranium. The results of modeling solution analyses from laboratory studies of uranyl phosphate solids, however, identified possible errors in the characterization of solids in the original solubility experiments. As part of this study, significant deficiencies in the WATEQ4 thermodynamic data base for uranium solutes and solids were corrected. Revisions included recalculation of selected uranium reactions. Additionally, thermodynamic data for the hydroxyl complexes of U(VI), including anionic (VI) species, were evaluated (to the extent permitted by the available data). Vanadium reactions were also added to the thermodynamic data base because uranium-vanadium solids can exist in natural ground-water systems. This study is only a partial validation of the WATEQ4 geochemical model because the available laboratory solubility studies do not cover the range of solid phases, alkaline pH values, and concentrations of inorganic complexing ligands needed to evaluate the potential solubility of uranium in ground waters associated with various proposed nuclear waste repositories. Further validation of this or other geochemical models for uranium will require careful determinations of uraninite solubility over the pH range of 7 to 10 under highly reducing conditions and of uranyl hydroxide and phosphate solubilities over the pH range of 7 to 10 under oxygenated conditions.

  18. Testing fundamentals: The chemical state of geochemical tracers in biominerals. (United States)

    Branson, O.; Redfern, S. A. T.; Read, E.; Elderfield, H.


    The use of many carbonate-derived geochemical proxies is underpinned by the assumption that tracer elements are incorporated 'ideally' as impurities the mineral lattice, following relatively straightforward kinetic and thermodynamic drives. This allows comparison to inorganic precipitation experiments, and provides a systematic starting point from which to translate geochemical tracers to environmental records. Biomineral carbonates are a prominent source of geochemical proxy material, and are far from an ideal inorganic system. They are structurally and compositionally heterogeneous mineral-organic composites, produced in tightly controlled biological environments, possibly via non-classical crystal growth mechanisms. Biominerals offer numerous opportunities for tracers to be incorporated in a 'non-ideal' state. For instance, tracers could be hosted within the organic component of the structure, in interstitial micro-domains of a separate mineral phase, or in localized high-impurity clusters. If a proxy element is hosted in a non-ideal state, our understanding of its incorporation and preservation is flawed, and the theoretical basis behind the proxies derived from it must be reevaluated. Thus far, the assumption of ideal tracer incorporation has remained largely untested, owing to the spatial resolution and sensitivity limits of available techniques. Developments in high-resolution, high-sensitivity X-ray spectroscopy at Scanning Transmission X-Ray Microscopes (STXMs) have allowed us to measure trace element coordination in foraminiferal calcite, at length-scales relevant to biomineralisation processes and tracer incorporation. This instrument has allowed us to test the fundamental assumptions behind several geochemical proxy elements. We present a summary of four STXM studies, assessing the chemical state and distribution of Mg (Branson et al, 2014), B (Branson et al, 2015), S and Na (unpub.), and highlight the implications of these data for the use of these

  19. Gliding Box method applied to trace element distribution of a geochemical data set (United States)

    Paz González, Antonio; Vidal Vázquez, Eva; Rosario García Moreno, M.; Paz Ferreiro, Jorge; Saa Requejo, Antonio; María Tarquis, Ana


    The application of fractal theory to process geochemical prospecting data can provide useful information for evaluating mineralization potential. A geochemical survey was carried out in the west area of Coruña province (NW Spain). Major elements and trace elements were determined by standard analytical techniques. It is well known that there are specific elements or arrays of elements, which are associated with specific types of mineralization. Arsenic has been used to evaluate the metallogenetic importance of the studied zone. Moreover, as can be considered as a pathfinder of Au, as these two elements are genetically associated. The main objective of this study was to use multifractal analysis to characterize the distribution of three trace elements, namely Au, As, and Sb. Concerning the local geology, the study area comprises predominantly acid rocks, mainly alkaline and calcalkaline granites, gneiss and migmatites. The most significant structural feature of this zone is the presence of a mylonitic band, with an approximate NE-SW orientation. The data set used in this study comprises 323 samples collected, with standard geochemical criteria, preferentially in the B horizon of the soil. Occasionally where this horizon was not present, samples were collected from the C horizon. Samples were taken in a rectilinear grid. The sampling lines were perpendicular to the NE-SW tectonic structures. Frequency distributions of the studied elements departed from normal. Coefficients of variation ranked as follows: Sb coefficients between Au, Sb, and As were found, even if these were low. The so-called ‘gliding box' algorithm (GB) proposed originally for lacunarity analysis has been extended to multifractal modelling and provides an alternative to the ‘box-counting' method for implementing multifractal analysis. The partitioning method applied in GB algorithm constructs samples by gliding a box of certain size (a) over the grid map in all possible directions. An "up

  20. Preliminary geothermal assessment surveys for the State of Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, D.M.; Cox, M.E.; Lienert, B.R.; Kauahikaua, J.P.; Mattice, M.D.


    The Geothermal Resource Assessment Program of the Hawaii Institute of Geophysics has conducted a series of geochemical and geophysical surveys in ten separate locations within the State of Hawaii in an effort to identify and assess potential geothermal areas throughout the state. The techniques applied include groundwater chemistry and temperatures, soil mercury surveys, ground radon emanometry, time-domain electromagnetic surveys and Schlumberger resistivity soundings. Although geochemical and geophysical anomalies were identified in nearly all the survey sites, those areas which show most promise, based on presently available data, for a geothermal resource are as follows: Puna, Kailua Kona, and Kawaihae on the island of Hawaii; Haiku-Paia and Olowalu-Ukumehame canyons on Maui; and Lualualei Valley on Oahu. Further surveys are planned for most of these areas in order to further define the nature of the thermal resource present.

  1. Water information bulletin No. 30: geothermal investigations in Idaho. Part 11. Geological, hydrological, geochemical and geophysical investigations of the Nampa-Caldwell and adjacent areas, southwestern Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, J.C. (ed.)


    The area under study included approximately 925 sq km (357 sq mi) of the Nampa-Caldwell portion of Canyon County, an area within the central portion of the western Snake River Plain immediately west of Boise, Idaho. Geologic mapping, hydrologic, geochemical, geophysical, including detailed gravity and aeromagnetic surveys, were run to acquire needed data. In addition, existing magnetotelluric and reflection seismic data were purchased and reinterpreted in light of newly acquired data.

  2. Petrological, organic geochemical and geochemical characteristics of coal from the Soko mine, Serbia

    Energy Technology Data Exchange (ETDEWEB)

    Zivotic, Dragana; Simic, Vladimir [Faculty of Mining and Geology, University of Belgrade, Djusina 7, 11000 Belgrade (RS); Wehner, Herman; Scheeder, Georg; Vidal, Angelika [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Stilleweg 2, 30655 Hannover (Germany); Cvetkovic, Olga; Sajnovic, Aleksandra [Center of Chemistry, IChTM, Studentski trg 16, 11000 Belgrade (RS); Jovancicevic, Branimir [Center of Chemistry, IChTM, Studentski trg 16, 11000 Belgrade (RS); Faculty of Chemistry, University of Belgrade, Studentski trg 16, 11000 Belgrade (RS); Grzetic, Ivan [Faculty of Chemistry, University of Belgrade, Studentski trg 16, 11000 Belgrade (RS); Ercegovac, Marko [Serbian Academy of Sciences and Arts, Knez Mihailova 35,11000 Belgrade (RS)


    A petrological, organic geochemical and geochemical study was performed on coal samples from the Soko Mine, Soko Banja basin, Serbia. Ten coal and two carbonaceous clay samples were collected from fresh, working faces in the underground brown coal mine from different parts of the main coal seam. The Lower Miocene, low-rank coal of the Soko Mine is a typical humic coal with huminite concentrations of up to 76.2 vol.%, liptinite less than 14 vol.% and inertinite less than 11 vol.%. Ulminite is the most abundant maceral with variable amounts of densinite and clay minerals. Sporinite and resinite are the most common macerals of the liptinite group. Inertodetrinite is the most abundant maceral of the inertinite group. The mineral-bituminous groundmass identified in some coal samples, and carbonaceous marly clay, indicate sub-aquatic origin and strong bacterial decomposition. The mean random huminite reflectance (ulminite B) for the main coal seam is 0.40 {+-} 0.05% Rr, which is typical for an immature to early mature stage of organic matter. The extract yields from the coal of the Soko Banja basin ranges from 9413 to 14,096 ppm, in which alkanes constituted 1.0-20.1%, aromatics 1.3-14.7%, asphaltenes 28.1-76.2% and resins 20.2-43.5%. The saturated hydrocarbon fractions included n-C{sub 15} to n-C{sub 32}, with an odd carbon number that predominate in almost all the samples. The contents of n-C{sub 27} and n-C{sub 29} alkanes are extremely high in some samples, as a contribution of epicuticular waxes from higher plants. Acyclic isoprenoid hydrocarbons are minor constituents in the aliphatic fraction, and the pristane/phytane (Pr/Ph) ratio varies between 0.56 and 3.13, which implies anaerobic to oxic conditions during sedimentation. The most abundant diterpanes were abietane, dehydroabietane and 16{alpha}(H)-phyllocladane. In samples from the upper part of the coal seam, diterpanes are the dominant constituents of the alkane fraction. Polycyclic alkanes of the triterpane

  3. INEEL Subregional Conceptual Model Report Volume 2: Summary of Existing Knowledge of Geochemical Influences on the Fate and Transport of Contaminants in the Subsurface at the INEEL

    Energy Technology Data Exchange (ETDEWEB)

    Paul L. Wichlacz; Robert C. Starr; Brennon Orr


    This document summarizes previous descriptions of geochemical system conceptual models for the vadose zone and groundwater zone (aquifer) beneath the Idaho National Engineering and Environmental Laboratory (INEEL). The primary focus is on groundwater because contaminants derived from wastes disposed at INEEL are present in groundwater, groundwater provides a pathway for potential migration to receptors, and because geochemical characteristics in and processes in the aquifer can substantially affect the movement, attenuation, and toxicity of contaminants. The secondary emphasis is perched water bodies in the vadose zone. Perched water eventually reaches the regional groundwater system, and thus processes that affect contaminants in the perched water bodies are important relative to the migration of contaminants into groundwater. Similarly, processes that affect solutes during transport from nearsurface disposal facilities downward through the vadose zone to the aquifer are relevant. Sediments in the vadose zone can affect both water and solute transport by restricting the downward migration of water sufficiently that a perched water body forms, and by retarding solute migration via ion exchange. Geochemical conceptual models have been prepared by a variety of researchers for different purposes. They have been published in documents prepared by INEEL contractors, the United States Geological Survey (USGS), academic researchers, and others. The documents themselves are INEEL and USGS reports, and articles in technical journals. The documents reviewed were selected from citation lists generated by searching the INEEL Technical Library, the INEEL Environmental Restoration Optical Imaging System, and the ISI Web of Science databases. The citation lists were generated using the keywords ground water, groundwater, chemistry, geochemistry, contaminant, INEL, INEEL, and Idaho. In addition, a list of USGS documents that pertain to the INEEL was obtained and manually searched

  4. Geochemical Parameters Required from the SKB Site Characterisation Programme

    Energy Technology Data Exchange (ETDEWEB)

    Bath, Adrian [Intellisci Ltd., Loughborough (United Kingdom)


    SKB has described its approach to site characterisation in a number of Technical Reports. One of the scientific topics in which specific information requirements and priorities are set out is geochemistry. This report for SKI examines critically whether the geochemical parameters identified in the SKB programme documents will be adequate for safety and regulatory requirements. It also examines some of the details of parameter requirements and interpretation tools that will be necessary to convert site investigation data into knowledge about chemical conditions and groundwater movements. The SKB strategy for geochemical data focuses on a small number of 'suitability indicators', primarily dissolved oxygen, pH and salinity. Their parameter requirements aim to assess those primary characteristics, as well as to acquire a wider range of data that will support those assessments and provide a broader understanding of candidate areas. An initial observation in this review that, though it is a primary suitability indicator, dissolved oxygen apparently will not be measured and instead will be inferred from other redox indicators. This raises a number of issues about sampling and monitoring measures, analytical data reliability and sensitivity, and the degree of confidence in geochemical understanding. A geochemical programme involves reconnaissance by desk study and acquisition of new data at levels of details that are appropriate to the stage of site investigations. As early as possible, a conceptual model of a candidate area should help to define the objectives of geochemical measurements on both rock and groundwater samples. It is recommended that parameters requirements should be defined and considered not only in terms of isolated measurements but more in terms of addressing broader objectives that relate to safety and also to geoscientific understanding. The safety priorities remain (e.g. dissolved oxygen) but will then be supported by an understanding of

  5. History and Progress of the North American Soil Geochemical Landscapes Project,2001-2010

    Institute of Scientific and Technical Information of China (English)

    David B.Smith; William F.Cannon; Laurel G.Woodruff; Francisco Moreira Rivera; Andrew N.Rencz; Robert G.Garrett


    In 2007,the U.S.Geological Survey,the Geological Survey of Canada,and the Mexican Geological Survey initiated a low-density(1 site per 1600 km2,13323 sites) geochemical and mineralogical survey of North American soils(North American Soil Geochemical Landscapes Project).Sampling and analytical protocols were developed at a series of workshops in 2003-2004 and pilot studies were conducted from 2004-2007.The ideal sampling protocol at each site includes a sample from 0-5 cm depth,a composite of the soil A horizon,and a sample from the soil C horizon.The 2-mm fraction of each sample is analyzed for Al,Ca,Fe,K,Mg,Na,S,Ti,Ag,Ba,Be,Bi,Cd,Ce,Co,Cr,Cs,Cu,Ga,In,La,Li,Mn,Mo,Nb,Ni,P,Pb,Rb,Sb,Sc,Sn,Sr,Te,Th,Tl,U,V,W,Y,and Zn by inductively coupled plasma-mass spectrometry and inductively coupled plasma-atomic emission spectrometry following a near-total digestion in a mixture of HCl,HNO3,HClO4,and HF.Separate methods are used for As,Hg,Se,and total C on this same size fraction.The major mineralogical components are determined by a quantitative X-ray diffraction method.Sampling in the conterminous U.S.was completed in 2010(c.4800 sites) with chemical and mineralogical analysis currently underway.In Mexico,approximately 66% of the sampling(871 sites) had been done by the end of 2010 with completion expected in 2012.After completing sampling in the Maritime provinces and portions of other provinces(472 sites,7.6% of the total),Canada withdrew from the project in 2010.Preliminary results for a swath from the central Florida clearly show the effects of soil parent material and climate on the chemical and mineralogical composition of soils.A sample archive will be established and made available for future investigations.

  6. Geochemical signature of columbite-tantalite and environmental impact of radioactive pegmatite mining in the Parelhas region, Rio Grande do Norte, Northeast Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Jorge Costa de; Cruz, Paulo R.; Pereira, Valmir, E-mail:, E-mail:, E-mail: [Comissao Nacional de Energia Nuclear (CNEN-RJ), Rio de Janeiro, RJ (Brazil); Ludka, Isabel P.; Mendes, Julio C., E-mail:, E-mail: [Universidade Federal de Rio do Janeiro (CCMN/UFRJ), Rio de Janeiro, RJ (Brazil). Centro de Ciencias Matematicas e da Natureza. Dept. de Geologia


    This article comprises geochemical, structural and radiometric investigations on radioactive pegmatites of the Borborema Pegmatitic Province in Northeast Brazil. The studied area is located in the surroundings of the city of Parelhas, in the geotectonic Province of Borborema. It is well known for its thousands of pegmatitic bodies exploited in primitive mines called garimpos. The main goal was to find an efficient, cheap and routine inspection procedure to identify the origin of commercialized radioactive columbite-tantalite (coltan) ore. The Brazilian Nuclear Energy Agency (CNEN) controls uranium commerce and nuclear activity in Brazil. Without an effective method to characterize coltan ores from different localities it is impossible to control the trade. The here presented new method was developed by correlating structural features of these pegmatites with the geochemical behavior of their coltan samples. It was found that the variation of U/Th vs. Nb{sub 2}O{sub 5}/Ta{sub 2}O{sub 5} provides geochemical signatures (analytical fingerprints) for the source location of such ore. The new method was tested with coltan samples of commercial batches from the Brazilian states of Amapa and Rondonia and also generated distinct geochemical signatures. A radiometric survey (CPS) to study the environmental impact of gamma radiation was also carried out in several mines and pegmatites. It included in situ measurements of pegmatite walls, enclosing rocks, soil, and accumulated water and revealed that gamma emitters are hardly solubilized and therefore environmental gamma radiation generally is not enhanced to a dangerous level. (author)

  7. Gamma-spectrometric surveys in differentiated granites. I: a review of the method and of the geochemical behavior of K, Th and U; Levantamentos gamaespectrometricos em granitos diferenciados. I: revisao da metodologia e do comportamento geoquimico dos elementos K, Th e U

    Energy Technology Data Exchange (ETDEWEB)

    Ulbrich, Horstpeter Herberto Gustavo Jose; Ulbrich, Mabel Norma Costas [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Dept. de Mineralogia e Geotectonica], e-mail:, e-mail:; Ferreira, Francisco Jose Fonseca [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Geologia. Lab. de Pesquisas em Geofisica Aplicada; Alves, Luizemara Soares [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)], e-mail:; Guimaraes, Gilson Burigo [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Dept. de Geociencias], e-mail:; Fruchting, Allan [Votorantim Metais, Sao Paulo, SP (Brazil)], e-mail:


    This contribution is part of a research project on the Neo proterozoic Cunhaporanga Granitic Complex (CGC), cropping out in the Ponta Grossa Arch (Parana state, SE Brazil). An initial study used the gamma-spectrometric data of the Serra do Mar Sul Aero geophysical Project, performed during the 70's for CPRM. Later, terrestrial gamma-spectrometric surveys focused on the study of the differentiated Joaquim Murtinho Granite (JMG) in the NW corner of CGC, and the Serra do Carambei Granite, to the SW. In this paper, the results obtained for JMG are presented in two parts. The first deals with methodology and the presentation of several gamma-spectrometric 'color-scale' maps, indicating that results obtained in granites depend strongly on a climatic factor, given the mobility of K during weathering in subtropical climates with strong rainfalls, also favoring a greater mobility of U. Minerals that are U and Th hosts, documented in granites, are reviewed, together with the weathering processes that control the mobility of K, U and Th in soils. Strong K signals in granitic areas submitted to these climates document the presence of fresh rock and/or effects of hydrothermal alteration, while weak or nil signals are evidence of strong leaching of K during weathering. U and Th will be retained in the residual soils, in part leading to their selective enrichment, also coupled with soil migration to lower topographic levels by colluvial transport. The larger solubility of U (as uranyl ion) allows its liberation under oxidizing conditions, and its migration, limited by the possibility of absorption in newly formed mineral and organic soil phases. Th should be retained almost totally in resistant phases and, when liberated in solution, will mostly be fixed in organic and inorganic soil substances. (author)

  8. Multi-element geochemical mapping in Southern China. (United States)

    Cheng, Zhizhong; Xie, Xuejing; Yao, Wensheng; Feng, Jizhou; Zhang, Qin; Fang, Jindong


    The 76-element Geochemical Mapping (76 GEM) Project was undertaken in southwestern China in 2000 and in southeastern China in 2008. In this project, 5244 composite samples of stream sediment at a density of one composite sample for each 1:50,000-scale map sheet were prepared from sample archives of the China Regional Geochemistry-National Reconnaissance (RGNR) Project, which have been available since 1978. The 76 elements were analyzed by using inductively coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence (XRF), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). In the present study, a new quality-control method known as the visualized standard map method was applied to the results of the 76 GEM project. Mean value and background value, which indicate the average concentration of the 76 elements in southern China, were derived from statistical data. Moreover, geochemical maps were compiled to demonstrate the distribution of the 76 elements in southern China.

  9. Environmental Status and geochemical assessment Sediments of Lake Skadar, Montenegro. (United States)

    Kastratović, Vlatko; Jaćimović, Željko; Bigović, Miljan; Đurović, Dijana; Krivokapić, Slađana


    The environmental mobility and geochemical partitioning of ten metals were examined in sediments collected from the six locations around Lake Skadar in Montenegro. A three-step sequential extraction procedure was used to determine the distribution of the metals in various substrates of lacustrine sediments, and the concentrations were measured in the liquid extract by ICP-OES. The largest portion of the total amount of cadmium, strontium and manganese can be found in sediment bound to the hydrated iron and manganese oxides; cobalt, lead, copper and nickel in the oxidizable fraction and the highest portion of chromium, vanadium and zinc are in the residual fraction. The most mobilized and potentially mobile metals are strontium, cadmium and cobalt while the most immobilized metals are chromium, vanadium and zinc. Based on geochemical parameters, an assessment of sediment contamination by the investigated metals was performed and the results showed potential risks ranging from "no risk" to "low risk" to the environment.

  10. Geochemical modeling of cyanide in tailing dam gold processing plant (United States)

    Khodadadi, Ahmad; Monjezi, M.; Mehrpouya, H.; Dehghani, H.


    This research is aimed at investigating possible neutralization of cyanide in tailing dam of Muteh gold processing plant in Isfahan, Iran at various conditions such as pH and temperature using USEPA Visual MINTEQ geochemical model simulation. The model is based on geochemical equilibrium which uses the simultaneous solution of the non-linear mass action expressions and linear mass balance relationships to formulate and solve the multiple-component chemical equilibrium problems. In this study the concentration of aqueous species in tailing dam as an aqueous, solid and gaseous were used as input in the model. Temperature and pH variation were simulated. The results of the model indicated that cyanide may be complexes in 10 < pH < 5. In other pH values complexation is not important. The results also indicated that cyanide reduction mechanism in acidic pH and temperature above 30°C is due to cyanide acid formation which is vaporized.

  11. Geochemical and Mineralogical Proxies for characterizing Tsunami and Paleotsunami Deposits (United States)

    Löwhagen, L.; Jankaew, K.; Kylander, M. E.; Skelton, A.; Wohlfarth, B.


    In this study we show how geochemistry and mineralogy can be used to correlate between previously dated tsunami and paleotsunami deposits in western Thailand. We do this based on cores from three parallel swales along a transect from the shoreline inland. Stratigraphy, together with geochemical and mineralogical analyses was used to correlate between tsunami and paleotsunami layers at these sites. Using element biplots (Ti-Zr, Ti-Y and Zr-Y) and mineralogical constraints, source signatures of each of the tsunami and paleotsunami layers were used to correlate between sand layers representing the 2004 tsunami and sand layers representing at least three paleotsunamis. Based on our correlations between these swales, we predict different inundation distances and directions for these paleotsunamis. Our study shows that a combination of geochemical and mineralogical analysis provides a powerful tool for correlation between tsunami and paleotsunami layers.

  12. Geochemical barriers for environment protection and recovery of nonferrous metals. (United States)

    Chanturiya, Valentine; Masloboev, Vladimir; Makarov, Dmitriy; Nesterov, Dmitriy; Bajurova, Julia; Svetlov, Anton; Men'shikov, Yuriy


    A study of natural minerals, ore tailings and their products as materials for artificial geochemical barriers is presented. In particular, it focuses on interaction between calcite and dolomite and sulfate solutions containing nickel, copper and iron under static conditions. Calcite of -0.1 mm fraction has been shown to perform well as a barrier when added to water phases of tailing dumps and natural reservoirs. Experiments under dynamic conditions have revealed a high potential of thermally activated copper-nickel tailings as barriers. After a 500-day precipitating period on a geochemical barrier, the contents of nickel and copper in ore dressing tailings were found to increase 12- and 28-fold, respectively. An effective sorbent of copper, iron and nickel ions is a brucite-based product of hydrochloric acid treatment of vermiculite ore tailings. Its sorption capacity can be essentially increased through thermal activation.

  13. Geochemical Constraints for Mechanisms of Planetary Differentiation and Volatile Depletion


    Dhaliwal, Jasmeet Kaur


    The evolution of the terrestrial planets involved a range of complex processes, including accretion, core formation, post-core formation accretion, mantle differentiation and volatile depletion. The earliest processes of accretion and core formation have largely been overprinted on Earth and Mars, but can be investigated using geochemical measurements of extraterrestrial materials. Highly siderophile elements (HSE; Os, Ir, Ru, Rh, Pt, Pd, Re, Au) preferentially partition into metal phases an...

  14. Geochemical signatures of tsunami deposits - what do they tell us? (United States)

    Chague-Goff, Catherine; Goff, James R.


    In the last two and half decades, but even more since the 2004 Indian Ocean Tsunami (IOT), there has been a significant increase in the amount of literature dealing with recent, historical and palaeotsunamis. Much has been written and debated about the diagnostic criteria of historical and palaeotsunami deposits. Most of the diagnostic criteria or proxies used reflect the expertise of the researchers involved and thus tend to be biased towards sedimentology, stratigraphy and micropalaeontology, with some reference to geomorphology, archaeology, anthropology and palynology. It should however be noted that all criteria have never been reported from one site, and neither are they all found in one single deposit. Thus, the lack of one or more proxies should not be taken as unique evidence to refute the tsunamigenic origin of a specific deposit. Although geochemical signatures have long been used as indicators for palaeosalinity in sedimentary sequences, there appears to have been some reluctance to use them to help in the identification of historical and palaeotsunami deposits. Like other proxies, geochemistry alone may not provide a definite answer to the origin of a deposit. Furthermore, poor preservation due to environmental conditions or as a result of post-diagenetic processes, might complicate the interpretation of geochemical signatures left by tsunami inundation. Similar taphonomic problems are also faced for microfossil proxies. However, geochemistry provides another piece to the puzzle, and together with other proxies, it can help identify palaeotsunami deposits. Geochemical signatures can also provide clues about the landward limit of runup of a tsunami, beyond the area of sediment deposition. This was recently documented following the 2004 IOT and the 2009 South Pacific tsunami. A summary of examples of geochemical signatures recorded in interstitial water and sediment of recent, historical and palaeotsunami deposits is presented.

  15. Geochemical characterization of the Nirano Mud Volcano Field (United States)

    Sciarra, Alessandra; Cantucci, Barbara; Ricci, Tullio; Conventi, Marzia


    Mud volcanoes, among fluid venting structures, are the most important phenomena related to natural seepage from the Earth's surface. The occurrence of mud volcanoes is controlled by several factors, such as tectonic activity and continuous hydrocarbon accumulation in a reservoir. Mud volcanoes in Italy occur along the external compressive margin of the Apennine chain. These mud volcanoes are usually small and unspectacular, when compared to other world examples. They rarely exhibit the periodic explosions, which is often related to important seismic activity. The Nirano Mud Volcano Field (NMVF) is located in the western sector of the Modena Apennine margin (Italy), which belongs to the Northern Apennines. The NMVF occurs over the crest of a thrust anticline associated with the main Pede-Apennine thrust and represents a good example of an onshore relationship between a mud volcano caldera structure and active thrust deformation, even if the fluid pathways are still not well understood at depth. The mud volcanoes are distributed along an area of about 10 ha, inside of the wider Natural Reserve, and are situated at the bottom of a wide sub-circular depression. The NMVF is currently formed by four main vents composed of a number of individual active cones (or gryphons) defining structural alignments trending ENE-WSW. A geochemical soil gas survey of 230 CO2 and CH4 fluxes and 150 CO2, CH4, Rn, He, H2 concentration measurements has been carried out inside the NMVF. Moreover, the fluid emissions from 4 active cones located in different sectors of NMVF have been sampled for chemical and isotopical analysis of water and free gas. The distribution of pathfinder elements as 222Rn, He e H2 has been studied in order to identify potential faults and/or fractures related to preferential migration pathways and the possible interactions between reservoir and surface. Soil gas data highlight two zones characterized by higher values, localized in the WSW and ENE of the NMVF area. In

  16. Geochemical characterization of oceanic basalts using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Iyer Sridhar D


    Full Text Available Abstract The geochemical discriminate diagrams help to distinguish the volcanics recovered from different tectonic settings but these diagrams tend to group the ocean floor basalts (OFB under one class i.e., as mid-oceanic ridge basalts (MORB. Hence, a method is specifically needed to identify the OFB as normal (N-MORB, enriched (E-MORB and ocean island basalts (OIB. We have applied Artificial Neural Network (ANN technique as a supervised Learning Vector Quantisation (LVQ to identify the inherent geochemical signatures present in the Central Indian Ocean Basin (CIOB basalts. A range of N-MORB, E-MORB and OIB dataset was used for training and testing of the network. Although the identification of the characters as N-MORB, E-MORB and OIB is completely dependent upon the training data set for the LVQ, but to a significant extent this method is found to be successful in identifying the characters within the CIOB basalts. The study helped to geochemically delineate the CIOB basalts as N-MORB with perceptible imprints of E-MORB and OIB characteristics in the form of moderately enriched rare earth and incompatible elements. Apart from the fact that the magmatic processes are difficult to be deciphered, the architecture performs satisfactorily.

  17. Geochemical characterization of oceanic basalts using Artificial Neural Network. (United States)

    Das, Pranab; Iyer, Sridhar D


    The geochemical discriminate diagrams help to distinguish the volcanics recovered from different tectonic settings but these diagrams tend to group the ocean floor basalts (OFB) under one class i.e., as mid-oceanic ridge basalts (MORB). Hence, a method is specifically needed to identify the OFB as normal (N-MORB), enriched (E-MORB) and ocean island basalts (OIB). We have applied Artificial Neural Network (ANN) technique as a supervised Learning Vector Quantisation (LVQ) to identify the inherent geochemical signatures present in the Central Indian Ocean Basin (CIOB) basalts. A range of N-MORB, E-MORB and OIB dataset was used for training and testing of the network. Although the identification of the characters as N-MORB, E-MORB and OIB is completely dependent upon the training data set for the LVQ, but to a significant extent this method is found to be successful in identifying the characters within the CIOB basalts. The study helped to geochemically delineate the CIOB basalts as N-MORB with perceptible imprints of E-MORB and OIB characteristics in the form of moderately enriched rare earth and incompatible elements. Apart from the fact that the magmatic processes are difficult to be deciphered, the architecture performs satisfactorily.

  18. Fault controlled geochemical properties in Lahendong geothermal reservoir Indonesia (United States)

    Brehme, Maren; Deon, Fiorenza; Haase, Christoph; Wiegand, Bettina; Kamah, Yustin; Sauter, Martin; Regenspurg, Simona


    Rock and fluid geochemical data from Lahendong, Indonesia, were analyzed to evaluate the influence of fault zones on reservoir properties. It was found that these properties depend on fault-permeability controlled fluid flow. Results from measurements of spring and well water as well as rocks and their hydraulic properties were combined with hydrochemical numerical modeling. The models show that the geothermal field consists of two geochemically distinct reservoir sections. One section is characterized by acidic water, considerable gas discharge and high geothermal-power productivity—all related to increased fault zone permeability. The other section is characterized by neutral water and lower productivity. Increased fluid flow in the highly fractured and permeable areas enhances chemical reaction rates. This results in strong alteration of their surrounding rocks. Numerical models of reactions between water and rock at Lahendong indicate the main alteration products are clay minerals. A geochemical conceptual model illustrates the relation between geochemistry and permeability and their distribution within the area. Our conceptual model illustrates the relation between geochemistry and fault-zone permeability within the Lahendong area. Further mapping of fault-related permeability would support sustainable energy exploitation by avoiding low-productive wells or the production of highly corroding waters, both there and elsewhere in the world.

  19. Geochemical influences and mercury methylation of a dental wastewater microbiome. (United States)

    Rani, Asha; Rockne, Karl J; Drummond, James; Al-Hinai, Muntasar; Ranjan, Ravi


    The microbiome of dental clinic wastewater and its impact on mercury methylation remains largely unknown. Waste generated during dental procedures enters the sewer system and contributes a significant fraction of the total mercury (tHg) and methyl mercury (MeHg) load to wastewater treatment facilities. Investigating the influence of geochemical factors and microbiome structure is a critical step linking the methylating microorganisms in dental wastewater (DWW) ecosystems. DWW samples from a dental clinic were collected over eight weeks and analyzed for geochemical parameters, tHg, MeHg and bacterio-toxic heavy metals. We employed bacterial fingerprinting and pyrosequencing for microbiome analysis. High concentrations of tHg, MeHg and heavy metals were detected in DWW. The microbiome was dominated by Proteobacteria, Actinobacteria, Bacteroidetes, Chloroflexi and many unclassified bacteria. Significant correlations were found between the bacterial community, Hg levels and geochemical factors including pH and the predicted total amount (not fraction) of neutral Hg-sulfide species. The most prevalent known methylators included Desulfobulbus propionicus, Desulfovibrio desulfuricans, Desulfovibrio magneticus and Geobacter sulfurreducens. This study is the first to investigate the impact of high loads of Hg, MeHg and other heavy metals on the dental clinic wastewater microbiome, and illuminates the role of many known and unknown sulfate-reducing bacteria in Hg methylation.

  20. Identifying paleotsunami deposits in Thailand using geochemical analyses (United States)

    Löwhagen, Linda; Jankaew, Kruawun; Kylander, Malin; Wohlfarth, Barbara


    Paleotsunami research has received considerable attention following the devastating Indian Ocean tsunami of December 2004. Specific questions involve the magnitude, frequency and impact of past tsunamis. Phra Thong Island in the eastern Andaman Sea is an ideal location to study paleotsunami deposits in great detail (Jankaew et al., 2008). Apart from the 2004 Indian Ocean tsunami layer, three more distinct tsunami layers, separated by soil horizons have been identified and dated (Jankaew et al., 2008). In a collaborative project between Stockholm University and Chulalongkorn University, four sites on Phra Thong Island were chosen for detailed geochemical studies and additional AMS 14C dating. Paleotsunami deposits at these sites can be seen as more or less distinct sand layers embedded between the peaty soils. Here we report the initial results of XRF core scanning and loss on ignition analysis, which are supplemented by new 14C dates. The XRF data sets show a good correlation between synchronous tsunami layers along a coast-inland transect. The geochemistry moreover suggests a change in source area for the oldest tsunami layer. Further work will focus on a detailed geochemical characterization of the tsunami and soil layers, and on the influence of soil processes on the geochemical record. Reference: Jankaew, K; Atwater, B; Sawai, Y; Choowong, M; Charoentitirat, T; Martin, M; Prendergast, A, 2008. Medieval forewarning of the 2004 Indian Ocean tsunami in Thailand. Nature 455, 1228-1231.

  1. Quality assurance and quality control of geochemical data—A primer for the research scientist (United States)

    Geboy, Nicholas J.; Engle, Mark A.


    Geochemistry is a constantly expanding science. More and more, scientists are employing geochemical tools to help answer questions about the Earth and earth system processes. Scientists may assume that the responsibility of examining and assessing the quality of the geochemical data they generate is not theirs but rather that of the analytical laboratories to which their samples have been submitted. This assumption may be partially based on knowledge about internal and external quality assurance and quality control (QA/QC) programs in which analytical laboratories typically participate. Or there may be a perceived lack of time or resources to adequately examine data quality. Regardless of the reason, the lack of QA/QC protocols can lead to the generation and publication of erroneous data. Because the interpretations drawn from the data are primary products to U.S. Geological Survey (USGS) stakeholders, the consequences of publishing erroneous results can be significant. The principal investigator of a scientific study ultimately is responsible for the quality and interpretation of the project's findings, and thus must also play a role in the understanding, implementation, and presentation of QA/QC information about the data. Although occasionally ignored, QA/QC protocols apply not only to procedures in the laboratory but also in the initial planning of a research study and throughout the life of the project. Many of the tenets of developing a sound QA/QC program or protocols also parallel the core concepts of developing a good study: What is the main objective of the study? Will the methods selected provide data of enough resolution to answer the hypothesis? How should samples be collected? Are there known or unknown artifacts or contamination sources in the sampling and analysis methods? Assessing data quality requires communication between the scientists responsible for designing the study and those collecting samples, analyzing samples, treating data, and

  2. Geochemical studies of backfill aggregates, lake sediment cores and the Hueco Bolson Aquifer (United States)

    Thapalia, Anita

    Aquifer that an important sources of water in the El Paso/Cd. Juraez metroplex. To delineate the boundary between fresh and brackish water from the northern Hueco Bolson Aquifer, we utilize an integrative geochemical, geophysical, and sedimentological approach. The goal of this study is to use geophysical well-log analysis and the water chemical analysis for identifying the changes in the quality of the groundwater. A detailed microgravity survey is utilized to explore the subsurface geological structures that control the conduits and/or barriers of groundwater flow. A detailed geochemical analysis of aquifer samples provide salinity of groundwater that will complement to the subsurface structures obtained from the geophysical study. This fundamental research in developing methods from an integrated approach to estimate aquifer quality can be used as an analog for similar studies in other arid regions.

  3. Gemas: Geochemical mapping of the agricultural and grasing land soils of Europe (United States)

    Reimann, Clemens; Fabian, Karl; Birke, Manfred; Demetriades, Alecos; Matschullat, Jörg; Gemas Project Team


    Geochemical Mapping of Agricultural and grazing land Soil (GEMAS) is a cooperative project between the Geochemistry Expert Group of EuroGeoSurveys and Eurometaux. During 2008 and until early 2009, a total of 2108 samples of agricultural (ploughed land, 0-20 cm, Ap-samples) and 2023 samples of grazing land (0-10 cm, Gr samples)) soil were collected at a density of 1 site/2500 km2 each from 33 European countries, covering an area of 5,600,000 km2. All samples were analysed for 52 chemical elements following an aqua regia extraction, 42 elements by XRF (total), and soil properties, like CEC, TOC, pH (CaCl2), following tight external quality control procedures. In addition, the Ap soil samples were analysed for 57 elements in a mobile metal ion (MMI®) extraction, Pb isotopes, magnetic susceptibility and total C, N and S. The results demonstrate that robust geochemical maps of Europe can be constructed based on low density sampling, the two independent sample materials, Ap and Gr, show very comparable distribution patterns across Europe. At the European scale, element distribution patterns are governed by natural processes, most often a combination of geology and climate. The geochemical maps reflect most of the known metal mining districts in Europe. In addition, a number of new anomalies emerge that may indicate mineral potential. The size of some anomalies is such that they can only be detected when mapping at the continental scale. For some elements completely new geological settings are detected. An anthropogenic impact at a much more local scale is discernible in the immediate vicinity of some major European cities (e.g., London, Paris) and some metal smelters. The impact of agriculture is visible for Cu (vineyard soils) and for some further elements only in the mobile metal ion (MMI) extraction. For several trace elements deficiency issues are a larger threat to plant, animal and finally human health at the European scale than toxicity. Taking the famous step

  4. Adaptive Multiscale Modeling of Geochemical Impacts on Fracture Evolution (United States)

    Molins, S.; Trebotich, D.; Steefel, C. I.; Deng, H.


    Understanding fracture evolution is essential for many subsurface energy applications, including subsurface storage, shale gas production, fracking, CO2 sequestration, and geothermal energy extraction. Geochemical processes in particular play a significant role in the evolution of fractures through dissolution-driven widening, fines migration, and/or fracture sealing due to precipitation. One obstacle to understanding and exploiting geochemical fracture evolution is that it is a multiscale process. However, current geochemical modeling of fractures cannot capture this multi-scale nature of geochemical and mechanical impacts on fracture evolution, and is limited to either a continuum or pore-scale representation. Conventional continuum-scale models treat fractures as preferential flow paths, with their permeability evolving as a function (often, a cubic law) of the fracture aperture. This approach has the limitation that it oversimplifies flow within the fracture in its omission of pore scale effects while also assuming well-mixed conditions. More recently, pore-scale models along with advanced characterization techniques have allowed for accurate simulations of flow and reactive transport within the pore space (Molins et al., 2014, 2015). However, these models, even with high performance computing, are currently limited in their ability to treat tractable domain sizes (Steefel et al., 2013). Thus, there is a critical need to develop an adaptive modeling capability that can account for separate properties and processes, emergent and otherwise, in the fracture and the rock matrix at different spatial scales. Here we present an adaptive modeling capability that treats geochemical impacts on fracture evolution within a single multiscale framework. Model development makes use of the high performance simulation capability, Chombo-Crunch, leveraged by high resolution characterization and experiments. The modeling framework is based on the adaptive capability in Chombo

  5. Principles of landscape-geochemical studies in the zones contaminated by technogenical radionuclides for ecological and geochemical mapping (United States)

    Korobova, Elena; Romanov, Sergey


    Efficiency of landscape-geochemical approach was proved to be helpful in spatial and temporal evaluation of the Chernobyl radionuclide distribution in the environment. The peculiarity of such approach is in hierarchical consideration of factors responsible for radionuclide redistribution and behavior in a system of inter-incorporated landscape-geochemical structures of the local and regional scales with due regard to the density of the initial fallout and patterns of radionuclide migration in soil-water-plant systems. The approach has been applied in the studies of distribution of Cs-137, Sr-90 and some other radionuclides in soils and vegetation cover and in evaluation of contribution of the stable iodine supply in soils to spatial variation of risk of thyroid cancer in areas subjected to radioiodine contamination after the Chernobyl accident. The main feature of the proposed approach is simultaneous consideration of two types of spatial heterogeneities: firstly, the inhomogeneity of external radiation exposure due to a complex structure of the contamination field, and, secondly, the landscape geochemical heterogeneity of the affected area, so that the resultant effect of radionuclide impact could significantly vary in space. The main idea of risk assessment in this respect was to reproduce as accurately as possible the result of interference of two surfaces in the form of risk map. The approach, although it demands to overcome a number of methodological difficulties, allows to solve the problems associated with spatially adequate protection of the affected population and optimization of the use of contaminated areas. In general it can serve the basis for development of the idea of the two-level structure of modern radiobiogeochemical provinces formed by superposition of the natural geochemical structures and the fields of technogenic contamination accompanied by the corresponding peculiar and integral biological reactions.

  6. Snowmelt Induced Hydrologic Perturbations Drive Dynamic Microbiological and Geochemical Behaviors across a Shallow Riparian Aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Danczak, Robert E.; Yabusaki, Steven B.; Williams, Kenneth H.; Fang, Yilin; Hobson, Chad; Wilkins, Michael J.


    Shallow riparian aquifers represent hotspots of biogeochemical activity in the arid western US. While these environments provide extensive ecosystem services, little is known of how natural environmental perturbations influence subsurface microbial communities and associated biogeochemical processes. Over a six-month period we tracked the annual snowmelt-driven incursion of groundwater into the vadose zone of an aquifer adjacent to the Colorado River, leading to increased dissolved oxygen (DO) concentrations in the normally suboxic saturated zone. Strong biogeochemical heterogeneity was measured across the site, with abiotic reactions between DO and sulfide minerals driving rapid DO consumption and mobilization of redox active species in reduced aquifer regions. Conversely, extensive DO increases were detected in less reduced sediments. 16S rRNA gene surveys tracked microbial community composition within the aquifer, revealing strong correlations between increases in putative oxygen-utilizing chemolithoautotrophs and heterotrophs and rising DO concentrations. The gradual return to suboxic aquifer conditions favored increasing abundances of 16S rRNA sequences matching members of the Microgenomates (OP11) and Parcubacteria (OD1) that have been strongly implicated in fermentative processes. Microbial community stability measurements indicated that deeper aquifer locations were relatively less affected by geochemical perturbations, while communities in shallower locations exhibited the greatest change. Reactive transport modeling of the geochemical and microbiological results supported field observations, suggesting that a predictive framework can be applied to develop a greater understanding of such environments. Frontiers in Earth Science Journal Impact & Description - ResearchGate - Impact Rankings ( 2015 and 2016 ). Available from: [accessed Jul 25, 2016].

  7. Reproducibility of Geochemical and Climate Signatures in Montastrea annularis (United States)

    Smith, J. M.; Quinn, T. M.; Halley, R. B.


    Geochemical variations in modern and fossil coral skeletons (Sr/Ca, Mg/Ca, δ 18O, δ 13C) are increasingly being used to reconstruct climate variability in tropical ocean-atmosphere system on interannual to centennial timescales. Coral-based climate studies are usually carried out using a single coral core from a reef, or a collection of cores covering different time intervals from the same reef site. Cross checking or replication - the generation of multiple climate time series from a single locality - is not a standard operating procedure in coral paleoclimatology because of the expense of generating additional geochemical time series. Quantitative assessment of intra-reef geochemical variability in multiple coral cores from the same reef is needed to verify the fidelity of climate reconstructions based on geochemical variations from a single coral. We perform such an assessment using the geochemical signals derived from two Montastrea annularis corals (LK1 and LK23) recovered in 2002 from Looe Key reef, Florida USA (24.5° N, 81.4° W). Looe Key is located in the central portion of the Florida Keys and has an hourly in situ seawater temperature record extending back to 1990. We extended this in situ SST record further back in time by splicing in HadISST 1.1 data extracted from the appropriate 1° by 1° grid point. Paired geochemical measurements of Sr/Ca, δ 18O and δ 13C were made by sampling coral LK1 and LK23 along their respective major growth axes. Geochemical variations versus depth were converted to monthly resolved time series extending from 2002-1966. The two ˜37 year coral time series replicate well in terms of both phasing and mean perspective: (δ 18O LK1, -3.90+/-0.28 ‰ , 1σ ; LK23, -3.93+/-0.31 ‰ , 1σ ), δ 13C (LK1, -0.80+/-0.68 ‰ , 1σ ; LK23, -0.72+/-0.59 ‰ , 1σ ) and Sr/Ca (LK1, 9.208+/-0.080 mmol/mol, 1σ ; LK23, 9.226+/-0.082 mmol/mol, 1σ ). Coral Sr/Ca-SST estimates of mean SST over the period 2002-1966 for LK1 (27.25+/-2.00

  8. Hydrothermal system of the Papandayan Volcano from temperature, self-potential (SP) and geochemical measurements (United States)

    Byrdina, Svetlana; Revil, André; Gunawan, Hendra; Saing, Ugan B.; Grandis, Hendra


    Papandayan volcano in West Java, Indonesia, is characterized by intense hydrothermal activities manifested by numerous fumaroles at three craters or kawah, i.e. Mas, Manuk and Baru. The latter was created after November 2002 phreatic eruption. Since 2011, numerous volcano-tectonic B events are encountered and the volcano was set on alert status on several occasions. The purpose of the present study is to delineate the structure of the summital hydrothermal system from Self-Potential (SP), soil temperature and gas concentrations in the soil (CO2, SO2 and H2S) data. This combination of geophysical and geochemical methods allows identification of the weak permeable zones serving as preferential pathways for hydrothermal circulation and potential candidates to future landslides or flank collapses. This study is an on-going collaborative research project and we plan to conduct electrical resistivity tomography (ERT) and also Induced-Polarization (IP) surveys. Additional data would allow the 3D imaging of the studied area. The IP parameters will be used to characterise and to quantify the degree of alteration of the volcanic rocks as has been shown very recently in the laboratory studies. There are also rocks and soil samples that will undergo laboratory analyses at ISTerre for IP and complex resistivity parameters at the sample scale that will help to interpret the survey results.

  9. Soil Gas Geochemical Behaviour across Buried and Exposed Faults during the 24 August 2016 Seismic Sequence (United States)

    Bigi, S.; Ciotoli, G.; Sciarra, A.; Ruggiero, L.; Annunziatellis, A.


    Following the earthquake (ML=6.0) of 24 August 2016 that affected large part of the central Apennine between the municipalities of Norcia (PG) and Amatrice (RI) (Central Italy), soil gas profiles (i.e., 222Rn, 220Rn, CO2 and CO2 flux) were carried out crossing buried and exposed coseismic fault rupture of the Mt. Vettore fault during the seismic sequence. The objective of the survey was to explore the migration mechanisms and the behaviour of different gas species near still-degassing active fault. Results provide higher gas and CO2 flux values (about twice for 222Rn and CO2 flux) in correspondence of the buried sector of the fault than those measured across the exposed fault rupture. Anomalous peaks due to advective migration are clearly visible along profile 1 on both side of the buried fault, whereas soil gas concentrations measured along profile 2 are mainly caused by shallow and still acting diffusive degassing associated faulting. The results confirm the usefulness of the soil gas survey to spatially recognise the shallow geometry of hidden faults, and to discriminate the geochemical migration mechanisms occurring at buried and exposed faults related to the seismic activity.

  10. Geologic field notes and geochemical analyses of outcrop and drill core from Mesoproterozoic rocks and iron-oxide deposits and prospects of southeast Missouri (United States)

    Day, Warren C.; Granitto, Matthew


    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources/Missouri Geological Survey, undertook a study from 1988 to 1994 on the iron-oxide deposits and their host Mesoproterozoic igneous rocks in southeastern Missouri. The project resulted in an improvement of our understanding of the geologic setting, mode of formation, and the composition of many of the known deposits and prospects and the associated rocks of the St. Francois terrane in Missouri. The goal for this earlier work was to allow the comparison of Missouri iron-oxide deposits in context with other iron oxide-copper ± uranium (IOCG) types of mineral deposits observed globally. The raw geochemical analyses were released originally through the USGS National Geochemical Database (NGDB, The data presented herein offers all of the field notes, locations, rock descriptions, and geochemical analyses in a coherent package to facilitate new research efforts in IOCG deposit types. The data are provided in both Microsoft Excel (Version Office 2010) spreadsheet format (*.xlsx) and MS-DOS text formats (*.txt) for ease of use by numerous computer programs.

  11. Identifying Groundwater Discharge Sources and Associated Geochemical Influences Using Resistivity Imaging and Geochemical Tracers in a Semi-Arid Estuary in South Texas (United States)

    Douglas, A. R.; Murgulet, D.; Spalt, N.


    The Nueces Bay (NB) system has been found to be ecologically unsound due to the loss/alteration of habitat and flow regimes required by indicator species and compromised nutrient cycling and sediment loading. The management practices of freshwater inflow regimes to NB concentrates on surface water flows and does not account for groundwater inflows, though submarine groundwater discharge (SGD) has been identified as a source of freshwater and limiting nutrients that could significantly impact bay salinities and nutrient loading. To encompass the range of spatio-temporal variabilities occurring between groundwater (GW) and surface-water (SW), multiple methods, including resistivity imaging, geochemical tracers, and radioisotopes, are applied in conjunction to identify SGD sources. Preliminary continuous resistivity profile surveys identified multiple possible GW upwelling paths from which thirteen stations were chosen in NB and two stations in Nueces River (NR). A Principal Component Analysis (PCA) of initial geochemical, nutrient and radioisotope data, shows that 76% of the variation in the data is explained by three factors: seasonality, freshwater inflows, and reducing environment. Significant seasonal variation is seen in average SW salinity (37psu in September 2014 to 4psu in June 2015), Ra-224 (359dpm/L in September to 636dpm/L in December), Ra-226 (268dpm/L in September to 570 dpm/L in December), ammonium (1.3μM in September to 5.5μM in April), and chlorophyll-α (3.99μg/L in December to 12.3 μg/L in April). Additionally, short-lived radioisotopes Rn-222 and Ra-224 are consistently elevated near the NR mouth, the inflow from Gum Hollow Creek, and a single station in the middle of the Bay indicating more localized, active SGD sources. However, only the stations in NR and at the NR mouth show consistently strong correlations to chlorophyll-α, phosphate, and silicate, with the river station closest to NB having the highest concentrations of nitrogen

  12. Metallogenetic characterization of granitoid rocks through geochemical prospection: the Lagoa Real example related to uranium mineralization in Bahia state, Brazil; Caracterizacao metalogenetica de corpos gratinoides atraves de prospeccao geoquimica: o exemplo da suite intrusiva Lagoa Real relacionada a mineralizacoes de uranio no Estado da Bahia

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, J.E., E-mail: [Servico Geologico do Brasil (GEREMI/SUREG/SA/CPRM), Salvador, BA (Brazil)


    Within a broad metallogenetic evaluation program carried out by CPRM - Geological Survey of Brazil in covenant with the CBPM - Companhia Baiana de Pesquisa Mineral in the central part of the Sao Francisco Craton, the Lagoa Real granitoid rocks was one of the selected targets. The work included geochemical exploration supplemented by follow-in survey and integrated 1:200.000 scale geochemical cartography. The Lagoa Real granitoid was recognized with composition ranging from monzogranitic to alcaligranitic type. The geochemical surveying led to the definition of the metallogenetic specialization of the granitoid rock, with characteristic geochemical and mineralogic associations. These associations are related to uranium mineralization. The genetic model using stream sediment and pan concentrate data, show similarity with the metallogenetic model of zonal partitioning proposed by Routhier (1963), for plutonogenic lode deposits with potential for Sn, W, Nb, Be, REE, Au, and U. In this work emphasis is given to the importance of the integrated use of different prospective methods toward the evaluation of granitoid systems, particularly the combination of geochemical surveying methods with results for a better understanding of the geologic and metallogenetic settings. (author)

  13. Evolution of Geochemical Variations Along the Central American Volcanic Front (United States)

    Saginor, I. S.; Gazel, E.; Condie, C.; Carr, M. J.


    New geochemical analyses of volcanic rocks in El Salvador add to existing data from Nicaragua and Costa Rica to create a comprehensive set of geochemical data for Central American volcanics. These data coupled with previously published 40Ar/39Ar ages covering the past 30 Ma shows that Costa Rica and Nicaragua had similar U/Th and Ba/La values until 10 Ma when the region developed the distinctive along arc variations that made this margin famous. U/Th values increased in Nicaragua since the Miocene, while remaining unchanged along the rest of the volcanic front. This coincides temporally with the Carbonate Crash, which caused a transition in Cocos plate sediments from low-U carbonates to high-U, organic rich hemipelagic muds. Increases in uranium are not observed in Costa Rica because its lower slab dip produces a more diffuse zone of partial melting and because of the contribution from Galapagos-derived tracks dilutes this signal. Ba/La has been used as a geochemical proxy for contributions from the subducting slab, however our analyses indicate that the Ba concentrations do not vary significantly along strike either in the subducting sediment or the volcanic front. Along-arc variation is controlled by changes in La, an indicator of the degree of partial melting or source enrichment. Trace element models of five segments of the volcanic front suggest that a subducting sediment component is more important to magmas produced in El Salvador and Nicaragua than in Costa Rica, where the geochemistry is controlled by recent (<10 Ma) recycling of Galapagos tracks.

  14. Leveling data in geochemical mapping: scope of application, pros and cons of existing methods (United States)

    Pereira, Benoît; Vandeuren, Aubry; Sonnet, Philippe


    Geochemical mapping successfully met a range of needs from mineral exploration to environmental management. In Europe and around the world numerous geochemical datasets already exist. These datasets may originate from geochemical mapping projects or from the collection of sample analyses requested by environmental protection regulatory bodies. Combining datasets can be highly beneficial for establishing geochemical maps with increased resolution and/or coverage area. However this practice requires assessing the equivalence between datasets and, if needed, applying data leveling to remove possible biases between datasets. In the literature, several procedures for assessing dataset equivalence and leveling data are proposed. Daneshfar & Cameron (1998) proposed a method for the leveling of two adjacent datasets while Pereira et al. (2016) proposed two methods for the leveling of datasets that contain records located within the same geographical area. Each discussed method requires its own set of assumptions (underlying populations of data, spatial distribution of data, etc.). Here we propose to discuss the scope of application, pros, cons and practical recommendations for each method. This work is illustrated with several case studies in Wallonia (Southern Belgium) and in Europe involving trace element geochemical datasets. References: Daneshfar, B. & Cameron, E. (1998), Leveling geochemical data between map sheets, Journal of Geochemical Exploration 63(3), 189-201. Pereira, B.; Vandeuren, A.; Govaerts, B. B. & Sonnet, P. (2016), Assessing dataset equivalence and leveling data in geochemical mapping, Journal of Geochemical Exploration 168, 36-48.

  15. Geochemical Study of Lichens in Tatun Volcano Group, North Taiwan (United States)

    Kuan, Ssu-Yu


    Tatun Volcano Group (TVG) is located in the northwest of Taipei, the capital of Taiwan. Although the last activity was 200000 years ago, it is critical to monitor TVG because it is nearby metropolitan area. This study is part of the monitoring program and attempts to observe the geochemical relationship between lichen and volcanic gas. Lichens have been extensively used for monitoring atmospheric quality. Lichen can live in critical environments and can accumulate metals from atmosphere due to lack of excretion mechanism. Moreover, lichen can live long and growth in a low rate; therefore, lichen geochemistry can represent an average in a long term manner. In TVG, fruticose lichen can be seldom found due to the high concentration of SO2 in the atmosphere. However, foliose lichen and crustose lichen are not rare in the study area. In this study, lichens were collected from TVG and Nan-ao Trail which is in non-volcanic area. The cations were measured by ICP-MS. The geochemical results were analyzed by principal components analysis (PCA). It shows that there is no significant difference among non-volcanic lichens and the non-volcanic lichens are located at an end-member of two distinct trends. It is believed that the non-volcanic lichens indicate a geochemical baseline in north Taiwan and two trends may represent the mixing between two different types of volcanic gases in TVG and geochemical baseline. In this study, rare earth elements (REEs) were also measured. The results of non-volcanic and TVG lichens were normalized by North America Shale and TVG andesite, respectively. Both obtain a flat REE pattern, which confirm that TVG lichens receive metals from volcanic origin and non-volcanic lichens give information of background geochemistry in north Taiwan. In addition, a middle REE enrichment and distinct Ce negative anomaly can be observed. According to the previous studies, middle REE enrichment may be achieved by the selected adsorption of middle REEs by organic

  16. Geochemical explorations for gold deposits at Goldfield, Nevada (United States)

    Ashley, Roger P.; Keith, William J.


    The main problem in geochemical exploration for gold ore bodies in the 40 km2 hydrothermally altered area at Goldfield is to decide which of the many silicified ledges exposed are most likely to yield deposits with additional subsurface exploration. We conclude that the most efficient way to search for exploration targets is to collect rock samples from the ledges and analyze for the following elements in decreasing order of priority: gold, lead and silver, bismuth, and mercury. These elements form relict hypogene aureoles restricted to the ledges and are not appreciably redistributed during supergene leaching.

  17. Geochemical characterization of oceanic basalts using artificial neural network

    Digital Repository Service at National Institute of Oceanography (India)

    Das, P.; Iyer, S.D.

    -MORB, E or P-MORB and T-MORB, respectively) or as OIB [5-7]. The discrimination diagrams provide a broad picture of the type of basalts but it is difficult to determine the basic characters that are involved in the geochemical classification of OFB based... classifications for each input pattern of the form. Some instances where LVQ architecture has being extensively used are for pattern recognition and seafloor classification [9] and character- isation of the seafloor sediments [10]. In this commu- nication we use...

  18. This year`s model: Geochemical modeling and groundwater quality

    Energy Technology Data Exchange (ETDEWEB)

    Tuchfeld, H.A.; Simmons, S.P.; Jesionek, K.S. [GeoSyntec Consultants, Walnut Creek, CA (United States)]|[GeoSyntec Consultants, Atlanta, GA (United States); Romito, A.A. [Browning-Ferris Industries, Inc., Houston, TX (United States)


    It has been determined that landfill gas migration is a source of volatile organic compounds (VOCs) in groundwater. This can occur through: direct partitioning of migrating gas constituents into the groundwater; alteration of the physiochemical properties of the groundwater; and by indirect means (such as migration of landfill gas condensate and vadose zone water contaminated by landfill gas). This article examines the use of geochemical modeling as a useful tool for differentiating the effects of municipal solid waste (MSW) landfill gas versus leachate on groundwater quality at MSW landfill sites.

  19. Geochemical association of plutonium in marine sediments from Palomares (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Anton, M.P. [Dept. de Geoquimica e Impacto Ambiental, CIEMAT, Madrid (Spain); Gasco, C. [Dept. de Geoquimica e Impacto Ambiental, CIEMAT, Madrid (Spain); Sanchez-Cabeza, J.A. [Dept. de Fisica, Univ. Autonoma de Barcelona (Spain); Pujol, L. [Dept. de Fisica, Univ. Autonoma de Barcelona (Spain)


    The geochemical association of plutonium in sediments from the marine ecosystem of Palomares has been studied. A sequential leaching technique using selective extractants has been employed to determine the percentages of Pu in the following forms: (a) readily available, (b) exchangeable and adsorbed to specific sites, (c) associated with organic matter, (d) sesquioxides, (e) residual. Plutonium was found to be associated mainly with phases (c), (d) and (e), and therefore, appears to be relatively immobile and not readily available to bottom feeding biota. The effect of different source terms on Pu distribution is also discussed. (orig.)

  20. Geochemical Precursors to Volcanic Activity at Mount St. Helens, USA (United States)

    Berlo, Kim; Blundy, Jon; Turner, Simon; Cashman, Kathy; Hawkesworth, Chris; Black, Stuart


    The importance of the interplay between degassing and crystallization before and after the eruption of Mount St. Helens (Washington, USA) in 1980 is well established. Here, we show that degassing occurred over a period of decades to days before eruptions and that the manner of degassing, as deduced from geochemical signatures within the magma, was characteristic of the eruptive style. Trace element (lithium) and short-lived radioactive isotope (lead-210 and radium-226) data show that ascending magma stalled within the conduit, leading to the accumulation of volatiles and the formation of lead-210 excesses, which signals the presence of degassing magma at depth.

  1. Geochemical variability of copper and iron in Oman margin sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Alagarsamy, R.

    : Microchem. J.: 91(1); 2009; 111-117 Geochemical variability of copper and iron in Oman Margin sediments R. ALAGARSAMY * Chemical Oceanography Division, National Institute of Oceanography, Council of Scientific and Industrial Research (C... in the upper 100 mm. The Mn 5 distribution in core 12687#8 (Fig. 3d) showed a similar distribution to that observed for copper. As determined by sequential leaching, however, there was no detectable non-detrital Mn observed in core 12687#10 (only Mn 5...

  2. Geochemical Characteristics of Sinian Manganese Deposits in China

    Institute of Scientific and Technical Information of China (English)


    Sinian is one of the main periods of the formation of manganese deposits in China. Sinian manganese deposits are mainly hosted in carbon-rich black shale and siliceous shale formed during the Sinian interglacial period. The composition of manganese ore is simple. The main ore mineral is manganiferous carbonates. The grade of manganese ore is about 16- 25%, with Mn/Fe>5 and P/Mn=0.006- 0.14. Based on the tectonic setting and geological and geochemical characteristics of manganese deposits, this paper discusses the process of migration and concentration of manganese and ore-forming conditions of Sinian manganese deposits in China.

  3. Geochemical analysis of soils and sediments, Coeur d'Alene drainage basin, Idaho: sampling, analytical methods, and results (United States)

    Box, Stephen E.; Bookstrom, Arthur A.; Ikramuddin, Mohammed; Lindsay, James


    This report presents the locations, descriptions, analytical procedures used, and an inter-lab comparison of over 1100 geochemical analyses of samples of soil and sediment in and downstream of a major lead-zinc-silver mining district in the Coeur d'Alene (CdA) drainage basin of northern Idaho. The samples fall in 3 broad categories: (1) samples from vertical profiles of floodplain soils in the valley of the main stem of the CdA River (767 samples) and of the South Fork of the CdA River (38 samples), (2) size fractionated surficial samples of sediment bedload within the channel of the South Fork of the CdA River (68 samples), and (3) samples from vertical profiles of sediment bedload within the channel of the main stem of the CdA River (260 samples). Five different laboratories contributed geochemical data for this report. Four of the five laboratories employed analytical methods that require sample dissolution prior to analysis; one laboratory (US Geological Survey) used analytical instrumentation (energy dispersive x-ray fluorescence [EDXRF]) that is applied to pulverized samples. Some dissolution procedures use four acids (hydrochloric, nitric, perchloric, and hydrofluoric; Eastern Washington University [EWU] Geochemical Laboratory and XRAL Laboratories, Inc.), others use two acids (nitric acid and aqua regia; CHEMEX Labs, Inc.), and some use only concentrated nitric acid (ACZ Laboratories, Inc.). Most analyses of dissolved samples were done by Inductively Coupled Plasma - Atomic Emission Spectroscopy (ICP-AES) or by ICP - MS (Mass Spectroscopy). Some analyses for Ag and K were done by Flame Atomic Absorption (FAA). Inter-laboratory comparisons are made for 6 elements: lead (Pb), zinc (Zn), iron

  4. Can pH and electrical conductivity monitoring reveal spatial and temporal patterns in wetland geochemical processes?

    Directory of Open Access Journals (Sweden)

    P. J. Gerla


    Full Text Available Carbonate reactions and equilibria play a dominant role in the biogeochemical function of many wetlands. The US Geological Survey PHREEQC computer code was used to model geochemical reactions that may be typical for wetlands with water budgets characterized by: (a input dominated by direct precipitation, (b interaction with groundwater, (c variable degrees of reaction with organic carbon, and (d different rates of evapotranspiration. Rainfall with a typical composition was progressively reacted with calcite and organic carbon at various rates and proportions using PHREEQC. Contrasting patterns of the results suggest that basic water quality data collected in the field can reveal differences in the geochemical processes in wetlands. Given a temporal record, these can signal subtle changes in surrounding land cover and use. To demonstrate this, temperature, pH, and electrical conductivity (EC were monitored for three years in five large wetlands comprising 48 sample sites in northwest Minnesota. EC and pH of samples ranged greatly – from 23 to 1300 μS cm−1 and 5.5 to 9. The largest range in pH was observed in small beach ridge wetlands, where two clusters are apparent: (1 low EC and a wide range of pH and (2 higher pH and EC. Large marshes within a glacial lake – till plain have a broad range of pH and EC, but depend on the specific wetland. Outlying data typically occurred in altered or disturbed areas. The inter-annual and intra-wetland consistency of the results suggests that each wetland system hosts characteristic geochemical conditions.

  5. Geochemical signatures of the diffuse CO2 emission from Brava volcanic system, Cape Verde (United States)

    Rodriguez, F.; Bandomo, Z.; Barros, I.; Dias Fonseca, J.; Fernandes, P.; Rodrigues, J.; Melian Rodriguez, G.; Padron, E.; Dionis, S.; Sonia, S.; Gonçalves, A.; Fernandes, A.; Hernandez Perez, P. A.; Perez, N.


    Brava (67 km2) the smallest of the populated Cape Verde islands, lies at the southwestern end of the archipelagic crescent. Brava volcanic system has no documented historical eruptions, but its youthful volcanic morphology and the fact that earthquake swarms still occur indicate the potential for future eruptions. A geochemical survey of diffuse gas emissions was carried out in Brava island during February and March 2010. For this survey 228 sampling sites were selected all over the island to perform soil CO2 efflux measurements, using a portable accumulation chamber and an IR sensor, and soil temperature measurements at a depth of 30-50 cm. Soil gas samples were collected at 40 cm depth for chemical (He, H2, N2, CO2, CH4, Ar and O2) and isotopic (δ13C-CO2) analysis in 32 selected sampling sites. CO2 efflux values ranged from non-detectable up to 1.343 g m-2 d-1. To quantify the total diffuse CO2 emission from Brava volcanic system, a CO2 efflux map was constructed using sequential Gaussian simulations (sGs). Most of the studied area showed background levels of CO2 efflux (˜2 g m-2 d-1), while peak levels (>1300 g m-2 d-1) were mainly identified at Vinagre and Baleia areas. The total diffuse CO2 output from Brava volcanic system was estimated about 41.6 t d-1. The analysis of the carbon isotopic signature of the CO2 in the soil atmosphere provides an insight for evaluating the origin of the diffuse CO2 emission. Observed δ13C-CO2 values ranged from -20.86 to -1.26 ‰. A binary plot of CO2 concentrations versus δ13C-CO2 values allows us to represent three major geochemical reservoirs (atmospheric air, volcanic gas, and biogenic gas) and their related mixing lines. The chemical and isotopic analysis of Brava soil gas samples suggest a mixing with deep-seated CO2 and biogenic gas for the diffuse CO2 emission from Brava volcanic system. The lack of visible volcanic gas emission in Brava highlights the importance of monitoring diffuse CO2 emission to improve its

  6. Resolving the Multi-scale Behavior of Geochemical Weathering in the Critical Zone Using High Resolution Hydro-geochemical Models (United States)

    Pandey, S.; Rajaram, H.


    This work investigates hydrologic and geochemical interactions in the Critical Zone (CZ) using high-resolution reactive transport modeling. Reactive transport models can be used to predict the response of geochemical weathering and solute fluxes in the CZ to changes in a dynamic environment, such as those pertaining to human activities and climate change in recent years. The scales of hydrology and geochemistry in the CZ range from days to eons in time and centimeters to kilometers in space. Here, we present results of a multi-dimensional, multi-scale hydro-geochemical model to investigate the role of subsurface heterogeneity on the formation of mineral weathering fronts in the CZ, which requires consideration of many of these spatio-temporal scales. The model is implemented using the reactive transport code PFLOTRAN, an open source subsurface flow and reactive transport code that utilizes parallelization over multiple processing nodes and provides a strong framework for simulating weathering in the CZ. The model is set up to simulate weathering dynamics in the mountainous catchments representative of the Colorado Front Range. Model parameters were constrained based on hydrologic, geochemical, and geophysical observations from the Boulder Creek Critical Zone Observatory (BcCZO). Simulations were performed in fractured rock systems and compared with systems of heterogeneous and homogeneous permeability fields. Tracer simulations revealed that the mean residence time of solutes was drastically accelerated as fracture density increased. In simulations that include mineral reactions, distinct signatures of transport limitations on weathering arose when discrete flow paths were included. This transport limitation was related to both advective and diffusive processes in the highly heterogeneous systems (i.e. fractured media and correlated random permeability fields with σlnk > 3). The well-known time-dependence of mineral weathering rates was found to be the most

  7. Survey and Assessment of Land Ecological Quality in Cixi City

    Institute of Scientific and Technical Information of China (English)

    Junbao; LIU; Zhiyuan; CHEN; Weifeng; PAN; Shaojuan; XIE


    Soil,atmosphere,water and quality of agricultural product constitute the content of land ecological quality.Cixi City,through survey pilot project of basic farmland quality,carried out high precision soil geochemical survey and survey of agricultural products,irrigation water and air quality,and established ecological quality evaluation model of land.Based on the evaluation of soil geochemical quality,we conducted comprehensive quality assessment of atmosphere,water,agricultural products,and assessed the ecological quality of agricultural land in Cixi City.The evaluation results show that the ecological quality of most agricultural land in Cixi City is excellent,and there is ecological risk only in some local areas such as urban periphery.The experimental results provide demonstration and basis for the fine management of basic farmland and ecological protection.

  8. Geochemical response to hydrologic change along land-sea interfaces (United States)

    Michael, H. A.; Yu, X.; LeMonte, J. J.; Sparks, D. L.; Kim, K. H.; Heiss, J.; Ullman, W. J.; Guimond, J. A.; Seyfferth, A.


    Coastal groundwater-surface water interfaces are hotspots of geochemical activity, where reactants contributed by different sources come in contact. Reactions that occur along these land-sea boundaries have important effects on fluxes and cycling of carbon, nutrients, and contaminants. Hydrologic perturbations can alter interactions by promoting mixing, changing redox state, and altering subsurface residence times during which reactions may occur. We present examples from field and modeling investigations along the Delaware coastline that illustrate the impacts of hydrologic fluctuations on geochemical conditions and fluxes in different coastal environments. Along the highly populated Wilmington coastline, soils are contaminated with heavy metals from legacy industrial practices. We show with continuous redox monitoring and sampling over tidal to seasonal timescales that arsenic is mobilized and immobilized in response to hydrologic change. Along a beach, modeling and long-term monitoring show the influence of tidal to seasonal changes in the mixing zone between discharging fresh groundwater and seawater in the intertidal beach aquifer and associated impacts on biogeochemical reactivity and denitrification. In a saltmarsh, hydrologic changes alter carbon dynamics, with implications for the discharge of dissolved organic carbon to the ocean and export of carbon dioxide and methane to the atmosphere. Understanding the impacts of hydrologic changes on both long and short timescales is essential for improving our ability to predict the global biogeochemical impacts of a changing climate.

  9. Evolution of geochemical conditions in SFL 3-5

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Fred [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Lindgren, M.; Skagius, K.; Wiborgh, M. [Kemakta Konsult AB, Stockholm (Sweden); Engkvist, I. [Barsebaeck Kraft AB (Sweden)


    The evolution of geochemical conditions in the repository for long-lived low- and intermediate-level waste, SFL 3-5, and in the vicinity of the repository are important when predicting the retention of radionuclides and the long-term stability of engineered barriers. In this study the initial conditions at different repository sites at 300 - 400 m depth, the influence of repository construction and operation, the expected conditions after repository closure and saturation, and the evolution in a long-term perspective are discussed. Groundwaters that are found at these depths have near-neutral pH and are reducing in character, but the composition can vary from saline to non-saline water. The water chemistry in the near-field will mainly be influenced by the composition of the groundwater and by the large amounts of cementitious material that can be found in the repository. Disturbances caused during construction and operation are not expected to be permanent. Studies of old concrete indicate that leaching of concrete is a slow process. The geochemical conditions in the repository are therefore expected to be stable and prevail for hundreds of thousand years. However, the evolution of the surrounding environment may influence the conditions in long-term perspective.

  10. Multivariate analysis relating oil shale geochemical properties to NMR relaxometry (United States)

    Birdwell, Justin E.; Washburn, Kathryn E.


    Low-field nuclear magnetic resonance (NMR) relaxometry has been used to provide insight into shale composition by separating relaxation responses from the various hydrogen-bearing phases present in shales in a noninvasive way. Previous low-field NMR work using solid-echo methods provided qualitative information on organic constituents associated with raw and pyrolyzed oil shale samples, but uncertainty in the interpretation of longitudinal-transverse (T1–T2) relaxometry correlation results indicated further study was required. Qualitative confirmation of peaks attributed to kerogen in oil shale was achieved by comparing T1–T2 correlation measurements made on oil shale samples to measurements made on kerogen isolated from those shales. Quantitative relationships between T1–T2 correlation data and organic geochemical properties of raw and pyrolyzed oil shales were determined using partial least-squares regression (PLSR). Relaxometry results were also compared to infrared spectra, and the results not only provided further confidence in the organic matter peak interpretations but also confirmed attribution of T1–T2 peaks to clay hydroxyls. In addition, PLSR analysis was applied to correlate relaxometry data to trace element concentrations with good success. The results of this work show that NMR relaxometry measurements using the solid-echo approach produce T1–T2 peak distributions that correlate well with geochemical properties of raw and pyrolyzed oil shales.

  11. Geochemical Evidence of Microbially-Mediated Subglacial Mineral Weathering (United States)

    Montross, S. N.; Skidmore, M. L.


    Interactions between dilute meltwater and fine-grained, freshly comminuted debris at the bed of temperate glaciers liberate significant solute. The proportions of solute produced in the subglacial environment via biotic and abiotic processes remains unknown, however, this work suggests the biotic contribution is substantial. Laboratory analyses of microbiological and geochemical properties of sediment and meltwater from the Haut Glacier d'Arolla (HGA) indicates that a metabolically active microbial community exists in water-saturated sediments at the ice-bedrock interface. Basal sediment slurries and meltwater were incubated in the laboratory for 100 days under near in situ subglacial conditions. Relative proportions of solute produced via abiotic v. biotic mineral weathering were analyzed by comparing the evolved aqueous chemistry of biologically active "live" sediment slurries with sterilized controls. Aqueous chemical analyses indicate an increase in solute produced from mineral weathering coupled with nitrate depletion in the biologically active slurries compared with the killed controls. These results infer that microbial activity at HGA is likely an important contributor to chemical weathering associated solute fluxes from the glaciated catchment. Due to the magnitude of past glaciations throughout geologic time (e.g., Neoproterozoic and Late-Pleistocene), and evidence that subglacial microbial activity impacts mineral weathering, greater consideration needs to be given to cold temperature biogeochemical weathering and its impact on global geochemical cycles.

  12. Delayed geochemical hazard: Concept, digital model and case study

    Institute of Scientific and Technical Information of China (English)

    CHEN Ming; FENG Liu; Jacques Yvon


    Delayed Geochemical Hazard (DGH briefly) presents the whole process of a kind of serious ecological and environmental hazard caused by sudden reactivation and sharp release of long-term accumulated pollutant from stable species to active ones in soil or sediment system due to the change of physical-chemical conditions (such as temperature, pH, Eh, moisture, the concentrations of organic matters, etc.) or the decrease of environment capacity. The characteristics of DGH are discussed. The process of a typical DGH can be expressed as a nonlinear polynomial. The points where the derivative functions of the first and second orders of the polynomial reach zero, minimum and maximum are keys for risk assessment and harzard pridication.The process and mechanism of the hazard is due to the transform of pollutant among different species principally. The concepts of "total releasable content of pollutant", TRCP, and "total concentration of active specie", TCAS, are necessarily defined to describe the mechanism of DGH. The possibility of the temporal and spatial propagation is discussed. Case study shows that there exists a transform mechanism of "gradual release" and "chain reaction" among the species of the exchangeable and the bounds to carbonate, iron and manganese oxides and organic matter, thus causing the delayed geochemical hazard.

  13. Soil Lysimeter Excavation for Coupled Hydrological, Geochemical, and Microbiological Investigations. (United States)

    Sengupta, Aditi; Wang, Yadi; Meira Neto, Antonio A; Matos, Katarena A; Dontsova, Katerina; Root, Rob; Neilson, Julie W; Maier, Raina M; Chorover, Jon; Troch, Peter A


    Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled Earth-system processes. Such knowledge is imperative in improving predictions of hydro-biogeochemical cycles, especially under climate change scenarios. We present an experimental method, designed to capture sub-surface heterogeneity of an initially homogeneous soil system. This method is based on destructive sampling of a soil lysimeter designed to simulate a small-scale hillslope. A weighing lysimeter of one cubic meter capacity was divided into sections (voxels) and was excavated layer-by-layer, with sub samples being collected from each voxel. The excavation procedure was aimed at detecting the incipient heterogeneity of the system by focusing on the spatial assessment of hydrological, geochemical, and microbiological properties of the soil. Representative results of a few physicochemical variables tested show the development of heterogeneity. Additional work to test interactions between hydrological, geochemical, and microbiological signatures is planned to interpret the observed patterns. Our study also demonstrates the possibility of carrying out similar excavations in order to observe and quantify different aspects of soil-development under varying environmental conditions and scale.

  14. Impact of geochemical stressors on shallow groundwater quality (United States)

    An, Y.-J.; Kampbell, D.H.; Jeong, S.-W.; Jewell, K.P.; Masoner, J.R.


    Groundwater monitoring wells (about 70 wells) were extensively installed in 28 sites surrounding Lake Texoma, located on the border of Oklahoma and Texas, to assess the impact of geochemical stressors to shallow groundwater quality. The monitoring wells were classified into three groups (residential area, agricultural area, and oil field area) depending on their land uses. During a 2-year period from 1999 to 2001 the monitoring wells were sampled every 3 months on a seasonal basis. Water quality assay consisted of 25 parameters including field parameters, nutrients, major ions, and trace elements. Occurrence and level of inorganics in groundwater samples were related to the land use and temporal change. Groundwater of the agricultural area showed lower levels of ferrous iron and nitrate than the residential area. The summer season data revealed more distinct differences in inorganic profiles of the two land use groundwater samples. There is a possible trend that nitrate concentrations in groundwater increased as the proportions of cultivated area increased. Water-soluble ferrous iron occurred primarily in water samples with a low dissolved oxygen concentration and/or a negative redox potential. The presence of brine waste in shallow groundwater was detected by chloride and conductivity in oil field area. Dissolved trace metals and volatile organic carbons were not in a form of concentration to be stressors. This study showed that the quality of shallow ground water could be related to regional geochemical stressors surrounding the lake. ?? 2005 Elsevier B.V. All rights reserved.

  15. Hydrological and geochemical investigations of selenium behavior at Kesterson Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.M.; Tokunaga, T.K.; Zawislanski, P.; Yee, A.W.; Daggett, J.S.; Oldfather, J.M.; Tsao, L.; Johannis, P.W.


    From 1985 to the present we have studied the behavior of selenium in various habitats and environments at Kesterson reservoir, shifting emphasis as remedial actions altered the physical setting. Investigations have evaluated the efficacy of several remedial alternatives, from innovative techniques relying on the complex geochemical behavior of selenium alternatives, from innovative techniques relying on the complex geochemical behavior of selenium in aquatic environments to conventional excavation schemes. Results of these studies supported two cost-effective remedial measures; drain water deliveries were terminated in 1986 and, in 1988, 1 million cubic yards of soil were imported and used to fill the low lying areas of the former Kesterson Reservoir. To date, these two actions appear to have eliminated the aquatic habitat that caused waterfowl death and deformity at Kesterson from the early 1980's to 1987. Biological, surface water and groundwater monitoring data collected by the USBR indicate that Kesterson is now a much safer environment than in past years when drainage water containing 300{mu}g/l of selenium was delivered to the Reservoir. The continued presence of a large inventory of selenium within the upper portions of unfilled areas of Kesterson Reservoir and immediately below the fill material requires that a continued awareness of the status of this inventory be maintained and improved upon. 83 refs., 130 figs., 19 tabs.

  16. Geochemical and Isotopic Interpretations of Groundwater Flow in the Oasis Valley Flow System, Southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    J.M. Thomas; F.C. Benedict, Jr.; T.P. Rose; R.L. Hershey; J.B. Paces; Z.E. Peterman; I.M. Farnham; K.H. Johannesson; A.K. Singh; K.J. Stetzenbach; G.B. Hudson; J.M. Kenneally; G.F. Eaton; D.K. Smith


    This report summarizes the findings of a geochemical investigation of the Pahute Mesa-Oasis Valley groundwater flow system in southwestern Nevada. It is intended to provide geochemical data and interpretations in support of flow and contaminant transport modeling for the Western and Central Pahute Mesa Corrective Action Units.

  17. Geochemical evaluation of CO2 injection and containment in a depleted gas field

    NARCIS (Netherlands)

    Tambach, T.J.; Koenen, M.; Wasch, L.J.; Bergen, F. van


    The short- and long-term geochemical impact of CO2 injection into a depleted gas reservoir (DGR) is investigated using reservoir/geochemical modeling with TOUGH2/TOUGHREACT and 1D kinetic diffusion modeling with PHREEQC (caprock/well-cement). Simulations of CO2 injection into the reservoir predict d

  18. Reactive surface area in geochemical models - Lessons learned from a natural analogue

    NARCIS (Netherlands)

    Koenen, M.; Wasch, L.J.


    Many uncertainties exist in geochemical modeling. Mineral reactive surface area is one of the uncertain parameters. QEMSCAN analyses are performed on sandstone samples from a Dutch CO2 natural analogue to determine reactive surface areas. Geochemical modeling is performed using QEMSCAN surface areas

  19. pplication of Fractal Technique for Analysis of Geophysical - Geochemical Databases in Tekieh Pb-Zn Ore Deposit (SE of Arak

    Directory of Open Access Journals (Sweden)

    Seyed Reza Mehrnia


    calculated based on measuring the fractal dimensional variations in the recursive patterns (Mehrnia, 2013. In practice, the Area-Concentration equations (Mandelbrot, 2005 were applied in resistivity, induction polarization, Pb and Zn datasets for achieving the nonlinear relationships in anomalous regions which were characterized by increasing in regression coefficients with more spatial correlation of the variable than linear statistics (Mehrnia, 2013. Results and Discussion This research showed that both linear and nonlinear statistics are able to estimate the spatial association of geochemical anomalies with geophysical variables. A meaningful increase in the regression coefficient was also revealed after measuring the self-similar peculiarities of concentration values on gridded plots (Salehi, 2004; Torkashvand et al., 2009. From the fractal point of view, Pb ore-minerals have been deposited in the western sub-region, while Zn mineralization seems to be extended in the depth of eastern alterations. Also a predictable geochemical zonation can be considered in the western target (meaningful Pb anomalies that is more patterned than the eastern halos according to geological observations (Momenzadeh and Ziseman, 1981 and mineralogical evidences (Salehi, 2004. An increase in Supra ore/Sub ore proportional content was measured in the western sub-region which indicated more reliable potential of Pb mineralization (Galena as a particular indication of sulfide-rich minerals than the same phases of ore forming processes in the eastern sub-region, although the content of Pb-ores rapidly decreases in the eastern target and is replaced by Zn minerals (Sphalerite as particular indication of sulfide-rich mineralization. Because power law relationships are significant in both geochemical and geophysical anomalies (Mehrnia, 2013 a detailed program including borehole geophysics and litho-geochemical land-surveys should be considered in the prospected regions. Therefore, upcoming phases

  20. Groundwater sources and geochemical processes in a crystalline fault aquifer (United States)

    Roques, Clément; Aquilina, Luc; Bour, Olivier; Maréchal, Jean-Christophe; Dewandel, Benoît; Pauwels, Hélène; Labasque, Thierry; Vergnaud-Ayraud, Virginie; Hochreutener, Rebecca


    The origin of water flowing in faults and fractures at great depth is poorly known in crystalline media. This paper describes a field study designed to characterize the geochemical compartmentalization of a deep aquifer system constituted by a graben structure where a permeable fault zone was identified. Analyses of the major chemical elements, trace elements, dissolved gases and stable water isotopes reveal the origin of dissolved components for each permeable domain and provide information on various water sources involved during different seasonal regimes. The geochemical response induced by performing a pumping test in the fault-zone is examined, in order to quantify mixing processes and contribution of different permeable domains to the flow. Reactive processes enhanced by the pumped fluxes are also identified and discussed. The fault zone presents different geochemical responses related to changes in hydraulic regime. They are interpreted as different water sources related to various permeable structures within the aquifer. During the low water regime, results suggest mixing of recent water with a clear contribution of older water of inter-glacial origin (recharge temperature around 7 °C), suggesting the involvement of water trapped in a local low-permeability matrix domain or the contribution of large scale circulation loops. During the high water level period, due to inversion of the hydraulic gradient between the major permeable fault zone and its surrounding domains, modern water predominantly flows down to the deep bedrock and ensures recharge at a local scale within the graben. Pumping in a permeable fault zone induces hydraulic connections with storage-reservoirs. The overlaid regolith domain ensures part of the flow rate for long term pumping (around 20% in the present case). During late-time pumping, orthogonal fluxes coming from the fractured domains surrounding the major fault zone are dominant. Storage in the connected fracture network within the

  1. Geochemical and isotopic characteristics of groundwater from Velenje Basin, Slovenia (United States)

    Kanduč, Tjaša; Grassa, Fausto; Mori, Nataša; Verbovšek, Timotej


    The Velenje Basin in Slovenia is one of the largest actively mined coal basins in central Europe, producing around 4 million tons of lignite per year. Large amounts of groundwater are extracted from aquifers to facilitate underground mining of coal, and coal seam gas outbursts are a serious mine safety concern. This study analyses the geochemical and isotopic composition of groundwater to provide a general understanding of hydrogeological and geochemical processes in groundwater. Thirty-eight groundwater samples were taken from dewatering objects in the mine and at the surface in years 2014-2015. Groundwater in the Triassic aquifer is dominated by hydrogen carbonate, calcium, magnesium and isotopic composition of dissolved inorganic carbon in the range from -19.3 to -2.8‰ indicating degradation of soil organic matter and dissolution of carbonate minerals. In contrast, groundwater in the Pliocene aquifers is enriched in magnesium, sodium, calcium, potassium, and silicon, and has high alkalinity, with isotopic composition of dissolved inorganic carbon in the range of -14.4 to +4.6‰ . Based on isotopic composition of dissolved inorganic carbon values in all aquifers (Pliocene and Triassic), influencing processes are the dissolution of carbonate minerals and dissolution of organic matter, and additionally methanogenesis in the Pliocene aquifers. Based on the Principal Component Analysis (PCA) we can conclude that following different types of groundwater in Velenje Basin could be distinguished based on geochemical and isotopic data: Triassic aquifers with higher pH and lower conductivity and chloride, Pliocene, Pliocene 1 and Pliocene 2 aquifers with lower pH and higher conductivity and chloride contents, and Pliocene 3 and Pliocene 2, 3 aquifers with the highest pH and lowest conductivity and chloride contents. Major dissolved gas component in groundwater are carbon dioxide, nitrogen and methane. Concentrations of dissolved gases dewatering Triassic strata are low

  2. Application of isotopic and hydro-geochemical methods in identifying sources of mine inrushing water

    Institute of Scientific and Technical Information of China (English)

    Dou Huiping; Ma Zhiyuan; Cao Haidong; Liu Feng; Hu Weiwei; Li Ting


    Isotopic and hydro-geochemical surveys were carried out to identify the source of mine inrushing water at the #73003 face in the Laohutai Mine.Based on the analysis of isotopes and hydro-chemical features of surface water,groundwater from different levels and the inrushing water,a special relationship between water at the #73003 face and cretaceous water has been found.The results show that the isotopic and hydro-chemical features of the inrushing water are completely different from those of other groundwater bodies,except for the cretaceous water.The isotopic and hydrochemical characteristics of cretaceous water are similar to the inrushing water of the #73003 face,which aided with obtaining the evidence for the possible source of the inrushing water at the #73003 face.The isotope calculations show that the inrushing water at the #73003 face is a mixture of cretaceous water and Quaternary water,water from the cretaceous conglomerate is the main source,accounting for 67% of the inrushing water,while the Quaternary water accounts for 33%.The conclusion is also supported by a study of inrushing-water channels and an active fault near the inrushing-water plot on the #73003 face.

  3. Geochemical Analyses of Geologic Materials from Areas of Critical Environmental Concern, Clark and Nye Counties, Nevada (United States)

    Ludington, Steve; Castor, Stephen B.; Budahn, James R.; Flynn, Kathryn S.


    INTRODUCTION An assessment of known and undiscovered mineral resources of selected areas administered by the Bureau of Land Management (BLM) in Clark and Nye Counties, Nevada was conducted by the U.S. Geological Survey (USGS), Nevada Bureau of Mines and Geology (NBMG), and University of Nevada, Las Vegas (UNLV). The purpose of this work was to provide the BLM with information for use in their long-term planning process in southern Nevada so that they can make better-informed decisions. The results of the assessment are in Ludington (2006). Existing information about the areas, including geology, geophysics, geochemistry, and mineral-deposit information was compiled, and field examinations of selected areas and mineral occurrences was conducted. This information was used to determine the geologic setting, metallogenic characteristics, and mineral potential of the areas. Twenty-five Areas of Critical Environmental Concern (ACECs) were identified by BLM as the object of this study. They range from tiny (less than one km2) to large (more than 1,000 km2). The location of the study areas is shown on Figure 1. This report includes geochemical data for rock samples collected by staff of the USGS and NBMG in these ACECs and nearby areas. Samples have been analyzed from the Big Dune, Ash Meadows, Arden, Desert Tortoise Conservation Center, Coyote Springs Valley, Mormon Mesa, Virgin Mountains, Gold Butte A and B, Whitney Pockets, Rainbow Gardens, River Mountains, and Piute-Eldorado Valley ACECs.

  4. Geochemical haloes as an indication of over oil and gas fields in the Arctic shelf (United States)

    Kholmiansky, Mikhail; Anokhin, Vladimir


    Hydrocarbon deposits at the Arctic shelf of Russia are a source of jet dispersion of heavy metals that forms haloes in sediments and in the bottom layer of sea water. The intensity of the haloes and their spatial position are jointly determined by geological structure of their source and the environment, i.e., hydrocarbon deposits in host rocks, seafloor lithodynamics and oceanographic factors. Based on theoretical works of Kholmyansky and Putikov (2000; 2006; 2008), an application of electrochemical modification of electric prospecting for offshore hydrocarbon exploration and detailed survey of the morphology of deposits was developed. Specialized equipment was developed for studies of electrochemical features of bottom water layer. With this equipment one can detect ion anomalies in water and determine the type of deposit as gas, gas hydrate, gas condensate or oil. At operation, the unit with equipment is towed underwater off the stern of research vessel. Type and configuration of deposits are determined based on occurrence of trace heavy metals detected by ion-selective electrodes. The proposed method was applied to study a few hydrocarbon fields in Barents and Kara seas in 2001 -2012 including Shtokman, Medyn, Polyarnoe, Prirazlomnoye and others. The results allowed us to trace the margins of the deposits in more detail, and geochemical data, in addition, showed the type of deposits. In general, the method has proven efficient and applicable to a wide range of hydrocarbon deposits.

  5. Geochemical occurrences of arsenic and fluoride in bedrock groundwater: a case study in Geumsan County, Korea. (United States)

    Ahn, Joo Sung


    Bedrock groundwaters in Geumsan County, Korea, were surveyed to investigate the distribution and geochemical behaviors of arsenic and fluoride, mobilized through geogenic processes. The concentrations were enriched up to 113 μg/L for arsenic and 7.54 mg/L for fluoride, and 16% of 150 samples exceeded World Health Organization drinking water guidelines for each element. Simple Ca-HCO(3) groundwater types and positive correlations with pH, Ca, SO(4), and HCO(3) were characteristics of high (>10 μg/L) As groundwaters. The oxidation reaction of sulfide minerals in metasedimentary rocks and locally mineralized zones seems to be ultimately responsible for the existence of arsenic in groundwater. Desorption process under high pH conditions may also control the arsenic mobility in the study area. High (>1.5 mg/L) F groundwaters were found in the Na-HCO(3) type and with greater depth. Fluoride seemed to be enriched by deep groundwater interaction with granitic rocks, and continuous supply to shallow Ca-HCO(3)-type groundwater kept the concentration high. In the study area, drinking water management should include periodic As and F monitoring in groundwater.

  6. Identification of hydrologic and geochemical pathways using high frequency sampling, REE aqueous sampling and soil characterization at Koiliaris Critical Zone Observatory, Crete

    Energy Technology Data Exchange (ETDEWEB)

    Moraetis, Daniel, E-mail: [Department of Environmental Engineering, Technical University of Crete, 73100 Chania (Greece); Stamati, Fotini; Kotronakis, Manolis; Fragia, Tasoula; Paranychnianakis, Nikolaos; Nikolaidis, Nikolaos P. [Department of Environmental Engineering, Technical University of Crete, 73100 Chania (Greece)


    Highlights: > Identification of hydrological and geochemical pathways within a complex watershed. > Water increased N-NO{sub 3} concentration and E.C. values during flash flood events. > Soil degradation and impact on water infiltration within the Koiliaris watershed. > Analysis of Rare Earth Elements in water bodies for identification of karstic water. - Abstract: Koiliaris River watershed is a Critical Zone Observatory that represents severely degraded soils due to intensive agricultural activities and biophysical factors. It has typical Mediterranean soils under the imminent threat of desertification which is expected to intensify due to projected climate change. High frequency hydro-chemical monitoring with targeted sampling for Rare Earth Elements (REE) analysis of different water bodies and geochemical characterization of soils were used for the identification of hydrologic and geochemical pathways. The high frequency monitoring of water chemical data highlighted the chemical alterations of water in Koiliaris River during flash flood events. Soil physical and chemical characterization surveys were used to identify erodibility patterns within the watershed and the influence of soils on surface and ground water chemistry. The methodology presented can be used to identify the impacts of degraded soils to surface and ground water quality as well as in the design of methods to minimize the impacts of land use practices.

  7. Lake Bogoria hot springs (Kenya): geochemical features and geothermal implications (United States)

    Cioni, R.; Fanelli, G.; Guidi, M.; Kinyariro, J. K.; Marini, L.


    Many boiling springs and fumaroles are present along the shores of Lake Bogoria, which is a closed-basin alkaline saline lake typical of African Rifts. Two different geothermal waters, both of Na-HCO 3 type have been recognized. The first, discharged by the boiling springs located along the western shores of the lake, comes from a shallow steam-heated thermal aquifer. Its temperature is close to 100°C, as indicated by chalcedony solubility, while the chloride content of these waters is slightly higher than 200 mg L -1. The second, recognizable in the southernmost boiling springs, is representative of a deeper and hotter geothermal reservoir. The occurrence of mixing and boiling processes complicates the interpretation of geochemical data. Nevertheless, a chloride content of about 660 mg L -1, an equilibrium temperature close to 170°C and a high carbon dioxide partial pressure, at least 10-20 bar, have been estimated for the deep geothermal reservoir.

  8. Geochemical Proxies for Enhanced Process Control of Underground Coal Gasification (United States)

    Kronimus, A.; Koenen, M.; David, P.; Veld, H.; van Dijk, A.; van Bergen, F.


    Underground coal gasification (UCG) represents a strategy targeting at syngas production for fuel or power generation from in-situ coal seams. It is a promising technique for exploiting coal deposits as an energy source at locations not allowing conventional mining under economic conditions. Although the underlying concept has already been suggested in 1868 and has been later on implemented in a number of field trials and even at a commercial scale, UCG is still facing technological barriers, impeding its widespread application. Field UCG operations rely on injection wells enabling the ignition of the target seam and the supply with oxidants (air, O2) inducing combustion (oxidative conditions). The combustion process delivers the enthalpy required for endothermic hydrogen production under reduction prone conditions in some distance to the injection point. The produced hydrogen - usually accompanied by organic and inorganic carbon species, e.g. CH4, CO, and CO2 - can then be retrieved through a production well. In contrast to gasification of mined coal in furnaces, it is difficult to measure the combustion temperature directly during UCG operations. It is already known that geochemical parameters such as the relative production gas composition as well as its stable isotope signature are related to the combustion temperature and, consequently, can be used as temperature proxies. However, so far the general applicability of such relations has not been proven. In order to get corresponding insights with respect to coals of significantly different rank and origin, four powdered coal samples covering maturities ranging from Ro= 0.43% (lignite) to Ro= 3.39% (anthracite) have been gasified in laboratory experiments. The combustion temperature has been varied between 350 and 900 ˚ C, respectively. During gasification, the generated gas has been captured in a cryo-trap, dried and the carbon containing gas components have been catalytically oxidized to CO2. Thereafter, the

  9. The Earth's heterogeneous mantle a geophysical, geodynamical, and geochemical perspective

    CERN Document Server

    Khan, Amir


    This book highlights and discusses recent developments that have contributed to an improved understanding of observed mantle heterogeneities and their relation to the thermo-chemical state of Earth's mantle, which ultimately holds the key to unlocking the secrets of the evolution of our planet. This series of topical reviews and original contributions address 4 themes. Theme 1 covers topics in geophysics, including global and regional seismic tomography, electrical conductivity and seismic imaging of mantle discontinuities and heterogeneities in the upper mantle, transition zone and lower mantle. Theme 2 addresses geochemical views of the mantle including lithospheric evolution from analysis of mantle xenoliths, composition of the deep Earth and the effect of water on subduction-zone processes. Theme 3 discusses geodynamical perspectives on the global thermo-chemical structure of the deep mantle. Theme 4 covers application of mineral physics data and phase equilibrium computations to infer the regional-scale ...

  10. A Simplified View of the Geochemical Diversity Surrounding Home Plate (United States)

    Yen, A. S.; Morris, R. V.; Clark, B. C.; Gellert, R.


    The Home Plate feature (Fig. 1) within the Inner Basin of the Columbia Hills consists of layered rocks and has been interpreted as an accumulation of pyroclastic deposits [1]. Samples analyzed by the Alpha Particle X-ray Spectrometer within 25 meters of the eastern margin of Home Plate exhibit a strikingly diverse range of geochemical compositions, including the highest levels of Mg, Si, K, Zn, and Ni measured at Gusev Crater. This wide range of chemical variability across the 40+ samples analyzed on and near Home Plate can be represented by contributions from only six primary components. This reconstruction is not reflected in the M ssbauer mineralogy suggesting that significant alteration of the contributing components has occurred.

  11. Geochemical implications of brine leakage into freshwater aquifers. (United States)

    Wunsch, Assaf; Navarre-Sitchler, Alexis K; McCray, John E


    CO(2) injection into deep saline formations as a way to mitigate climate change raises concerns that leakage of saline waters from the injection formations will impact water quality of overlying aquifers, especially underground sources of drinking water (USDWs). This paper aims to characterize the geochemical composition of deep brines, with a focus on constituents that pose a human health risk and are regulated by the U.S. Environmental Protection Agency (USEPA). A statistical analysis of the NATCARB brine database, combined with simple mixing model calculations, show total dissolved solids and concentrations of chloride, boron, arsenic, sulfate, nitrate, iron and manganese may exceed plant tolerance or regulatory levels. Twelve agricultural crops evaluated for decreased productivity in the event of brine leakage would experience some yield reduction due to increased TDS at brine-USDW ratios of United States are almost three times higher than public and domestic withdrawals.

  12. Geochemical and hydrologic data for San Marcos Springs recharge characterization near San Marcos, Texas, November 2008--December 2010 (United States)

    Crow, Cassi L.


    During 2008–10, the U.S. Geological Survey, in cooperation with the San Antonio Water System, collected geochemical and hydrologic data in Bexar, Comal, and Hays Counties, Texas, to define and characterize the sources of recharge to San Marcos Springs. Precipitation samples were collected for stable isotope analysis at 1 site and water-quality samples were collected at 7 springs, 21 wells, and 9 stream sites in the study area between November 2008 and December 2010. Continuous water-quality monitors were installed in three springs, two wells, and at one stream site. Three continuous stream-gaging stations were installed to measure gage height and a stagedischarge rating was developed at two of the three sites. Depth to water below land surface was continuously measured in two wells.

  13. User’s guide for GcClust—An R package for clustering of regional geochemical data (United States)

    Ellefsen, Karl J.; Smith, David B.


    GcClust is a software package developed by the U.S. Geological Survey for statistical clustering of regional geochemical data, and similar data such as regional mineralogical data. Functions within the software package are written in the R statistical programming language. These functions, their documentation, and a copy of the user’s guide are bundled together in R’s unit of sharable code, which is called a “package.” The user’s guide includes step-by-step instructions showing how the functions are used to cluster data and to evaluate the clustering results. These functions are demonstrated in this report using test data, which are included in the package.

  14. Geochemical processes during five years of aquifer storage recovery. (United States)

    Herczeg, Andrew L; Rattray, Karen J; Dillon, Peter J; Pavelic, Paul; Barry, Karen E


    A key factor in the long-term viability of aquifer storage recovery (ASR) is the extent of mineral solution interaction between two dissimilar water types and consequent impact on water quality and aquifer stability. We collected geochemical and isotopic data from three observation wells located 25, 65, and 325 m from an injection well at an experimental ASR site located in a karstic, confined carbonate aquifer in South Australia. The experiment involved five major injection cycles of a total of 2.5 x 10(5) m3 of storm water (total dissolved solids [TDS] approximately 150 mg/L) into the brackish (TDS approximately 2400 mg/L) aquifer. Approximately 60% of the mixture was pumped out during the fifth year of the experiment. The major effect on water quality within a 25 m radius of the injection well following injection of storm water was carbonate dissolution (35 +/- 6 g of CaCO3 dissolved/m3 of aquifer) and sulfide mineral oxidation (50 +/- 10 g as FeS2/m3 after one injection). < 0.005% of the total aquifer carbonate matrix was dissolved during each injection event, and approximately 0.2% of the total reduced sulfur. Increasing amounts of ambient ground water was entrained into the injected mixture during each of the storage periods. High 14C(DIC) activities and slightly more negative delta13C(DIC) values measured immediately after injection events show that substantial CO2(aq) is produced by oxidation of organic matter associated with injectant. There were no detectable geochemical reactions while pumping during the recovery phase in the fifth year of the experiment.

  15. WATEQ3 geochemical model: thermodynamic data for several additional solids

    Energy Technology Data Exchange (ETDEWEB)

    Krupka, K.M.; Jenne, E.A.


    Geochemical models such as WATEQ3 can be used to model the concentrations of water-soluble pollutants that may result from the disposal of nuclear waste and retorted oil shale. However, for a model to competently deal with these water-soluble pollutants, an adequate thermodynamic data base must be provided that includes elements identified as important in modeling these pollutants. To this end, several minerals and related solid phases were identified that were absent from the thermodynamic data base of WATEQ3. In this study, the thermodynamic data for the identified solids were compiled and selected from several published tabulations of thermodynamic data. For these solids, an accepted Gibbs free energy of formation, 0//sub f,298/, was selected for each solid phase based on the recentness of the tabulated data and on considerations of internal consistency with respect to both the published tabulations and the existing data in WATEQ3. For those solids not included in these published tabulations, Gibbs free energies of formation were calculated from published solubility data (e.g., lepidocrocite), or were estimated (e.g., nontronite) using a free-energy summation method described by Mattigod and Sposito (1978). The accepted or estimated free energies were then combined with internally consistent, ancillary thermodynamic data to calculate equilibrium constants for the hydrolysis reactions of these minerals and related solid phases. Including these values in the WATEQ3 data base increased the competency of this geochemical model in applications associated with the disposal of nuclear waste and retorted oil shale. Additional minerals and related solid phases that need to be added to the solubility submodel will be identified as modeling applications continue in these two programs.

  16. Integrated Geochemical-Petrographic Insights on Neoproterozoic Ocean Oxygenation (United States)

    Hood, A.; Planavsky, N.; Wallace, M. W.; Wang, X.; Gueguen, B.


    Novel isotope systems have the potential to provide new insights into biogeochemical cycling in Earth's evolving oceans. However, much recent paleo-redox work has been done without extensive consideration of sample preservation or paleoenvironmental setting. Neoproterozoic reef complexes from South Australia provide a perfect setting to test geochemical redox proxies (e.g. uranium isotopes and trace metal chemistry) within a well-defined sedimentological and petrographic context. These reefs developed significant frameworks over ~1km of steep platform relief from the seafloor, and contain a variety of carbonate components including primary dolomite marine cements. Analysis of a variety of components within these reefs reveals significant variation in uranium isotope composition and trace metal chemistry between components, even within a single sample. Marine cements, which precipitated directly from seawater, have much lower contamination element concentrations (e.g. Al, Zr, Th) than depositional micrites, and appear to represent the best archive of ancient ocean conditions. These cements have high levels of Fe, Mn in shallow and deep reef facies (e.g. 2-3wt% Fe), but only Fe-oxide inclusions in peritidal settings. This distribution suggests ferruginous conditions under a surficial chemocline in this Neoproterozoic seawater. Uranium isotopes from pristine marine cements have relatively heavy values compared to modern seawater (median = -0.22 δ238U). These values are essentially unfractionated from riverine inputs, which we interpret as tracking extensive near quantitative low-T reduction of U(VI) to U(IV) by abundant soluble iron in seawater. Depositional components and late stage cements have a much lighter and more variable U isotope compositions (-0.71 to -0.08 δ238U). This work highlights the need for fundamental petrographic constraints on the preservation of depositional geochemical signatures in the future use and development of sedimentary redox proxies.

  17. Geophysical and geochemical signatures of Gulf of Mexico seafloor brines

    Directory of Open Access Journals (Sweden)

    S. B. Joye


    Full Text Available Geophysical, temperature, and discrete depth-stratified geochemical data illustrate differences between an actively venting mud volcano and a relatively quiescent brine pool in the Gulf of Mexico along the continental slope. Geophysical data, including laser-line scan mosaics and sub-bottom profiles, document the dynamic nature of both environments. Temperature profiles, obtained by lowering a CTD into the brine fluid, show that the venting brine was at least 10°C warmer than the bottom water. At the brine pool, two thermoclines were observed, one directly below the brine-seawater interface and a second about one meter below the first. At the mud volcano, substantial temperature variability was observed, with the core brine temperature being either slightly (~2°C in 1997 or substantially (19°C in 1998 elevated above bottom water temperature. Geochemical samples were obtained using a device called the "brine trapper" and concentrations of dissolved gases, major ions and nutrients were determined using standard techniques. Both brines contained about four times as much salt as seawater and steep concentration gradients of dissolved ions and nutrients versus brine depth were apparent. Differences in the concentrations of calcium, magnesium and potassium between the two brine fluids suggests that the fluids are derived from different sources or that brine-sediment reactions are more important at the mud volcano than the brine pool. Substantial concentrations of methane and ammonium were observed in both brines, suggesting that fluids expelled from deep ocean brines are important sources of methane and dissolved inorganic nitrogen to the surrounding environment.


    Institute of Scientific and Technical Information of China (English)

    Jens R.VALEUR; Steen LOMHOLT; Christian KNUDSEN


    A fixed link (tunnel and bridge,in total 16 km) was constructed between Sweden and Denmark during 1995-2000.As part of the work,approximately 16 million tonnes of seabed materials (limestone and clay till) were dredged,and about 0.6 million tonnes of these were spilled in the water.Modelling of the spreading and sedimentation of the spilled sediments took place as part of the environmental monitoring of the construction activities.In order to verify the results of the numerical modelling of sediment spreading and sedimentation,a new method with the purpose of distinguishing between the spilled sediments and the naturally occurring sediments was developed.Because the spilled sediments tend to accumulate at the seabed in areas with natural sediments of the same size,it is difficult to separate these based purely on the physical properties.The new method is based on the geo-chemical differences between the natural sediment in the area and the spill.The basic properties used are the higher content of calcium carbonate material in the spill as compared to the natural sediments and the higher Ca/Sr ratio in the spill compared to shell fragments dominating the natural calcium carbonate deposition in the area.The reason for these differences is that carbonate derived from recent shell debris can be discriminated from Danien limestone,which is the material in which the majority of the dredging took place,on the basis of the Ca/Sr ratio being 488 in Danien Limestone and 237 in shell debris.The geochemical recognition of the origin of the sediments proved useful in separating the spilled from the naturally occurring sediments.Without this separation,validation of the modelling of accumulation of spilled sediments would not have been possible.The method has general validity and can be used in many situations where the origin ora given sediment is sought.

  19. The geochemical constraints on Earth's accretion and core formation (Invited) (United States)

    Rudge, J. F.; Kleine, T.; Bourdon, B.


    There are now a wide range of geochemical observations that can be used to place constraints on Earth's first hundred million years. During this time the Earth accreted through collisions between numerous planetary embryos, and these collisions are thought to have caused significant melting and segregation of metal, forming the Earth's core. Information on the pressure, temperature, and oxygen fugacity conditions of core formation can be obtained from the abundances of siderophile elements in Earth's mantle and high pressure partitioning experiments. Timing information can be obtained from isotopic measurements, notably Hf-W and U-Pb. Here we present a simple geochemical box model that can be used to provide constraints on Earth's accretion and core formation. A key parameter in the model is the degree of equilibration during metal-silicate segregation. Existing models have shown that the siderophile element abundances are consistent with full equilibration in a deep magma ocean, with an increase in oxygen fugacity during accretion. Here we show that the siderophile element abundances are equally consistent with scenarios involving partial equilibration. The Hf-W isotopic observations constrain the degree of equilibration to be at least 36%. The timing constraints depend strongly on the degree of equilibration, but nevertheless bounds can be placed on the timing of Earth's accretion. With full equilibration, the Hf-W observations imply a rapid early accretion stage (at least 80% of Earth accreting within 35 Myr), but with partial equilibration accretion may be much more protracted. If Pb partitions into Earth’s core, the U-Pb observations can be used to constrain the late stages of accretion, and are consistent with the final 10% of Earth’s accretion occurring during the Moon-forming giant impact at ~4.45Ga.

  20. Experimental study on neptunium migration under in situ geochemical conditions (United States)

    Kumata, M.; Vandergraaf, T. T.


    Results are reported for migration experiments performed with Np under in situ geochemical conditions over a range of groundwater flow rates in columns of crushed rock in a specially designed facility at the 240-level of the Underground Research Laboratory (URL) near Pinawa, Manitoba, Canada. This laboratory is situated in an intrusive granitic rock formation, the Lac du Bonnet batholith. Highly altered granitic rock and groundwater were obtained from a major subhorizontal fracture zone at a depth of 250 m in the URL. The granite was wet-crushed and wet-sieved with groundwater from this fracture zone. The 180-850-μm size fraction was selected and packed in 20-cm long, 2.54-cm in diameter Teflon™-lined stainless steel columns. Approximately 30-ml vols of groundwater containing 3HHO and 237Np were injected into the columns at flow rates of 0.3, 1, and 3 ml/h, followed by elution with groundwater, obtained from the subhorizontal fracture, at the same flow rates, for a period of 95 days. Elution profiles for 3HHO were obtained, but no 237Np was detected in the eluted groundwater. After terminating the migration experiments, the columns were frozen, the column material was removed and cut into twenty 1-cm thick sections and each section was analyzed by gamma spectrometry. Profiles of 237Np were obtained for the three columns. A one-dimensional transport model was fitted to the 3HHO breakthrough curves to obtain flow parameters for this experiment. These flow parameters were in turn applied to the 237Np concentration profiles in the columns to produce sorption and dispersion coefficients for Np. The results show a strong dependence of retardation factors ( Rf) on flow rate. The decrease in the retarded velocity of the neptunium ( Vn) varied over one order of magnitude under the geochemical conditions for these experiments.

  1. Geophysical and geochemical signatures of Gulf of Mexico seafloor brines

    Directory of Open Access Journals (Sweden)

    S. B. Joye


    Full Text Available Geophysical, temperature, and discrete depth-stratified geochemical data illustrate differences between an actively venting mud volcano and a relatively quiescent brine pool in the Gulf of Mexico along the continental slope. Geophysical data, including laser-line scan mosaics and sub-bottom profiles, document the dynamic nature of both environments. Temperature profiles, obtained by lowering a CTD into the brine fluid, show that the venting brine was at least 10°C warmer than the bottom water. At the brine pool, thermal stratification was observed and only small differences in stratification were documented between three sampling times (1991, 1997 and 1998. In contrast, at the mud volcano, substantial temperature variability was observed, with the core brine temperature being slightly higher than bottom water (by 2°C in 1997 but substantially higher than bottom water (by 19°C in 1998. Detailed geochemical samples were obtained in 2002 using a device called the 'brine trapper' and concentrations of dissolved gases, major ions and nutrients were determined. Both brines contained about four times as much salt as seawater and steep concentration gradients of dissolved ions and nutrients versus brine depth were apparent. Differences in the concentrations of calcium, magnesium and potassium between the two brine fluids suggest that the fluids are derived from different sources, have different dilution/mixing histories, or that brine-sediment reactions are more important at the mud volcano. Substantial concentrations of methane, ammonium, and silicate were observed in both brines, suggesting that fluids expelled from deep ocean brines are important sources of these constituents to the surrounding environment.

  2. Arsenic: geochemical distribution and health risk in Italy (United States)

    Zuzolo, Daniela; Cicchella, Domenico; Albanese, Stefano; Catani, Vittorio; Dinelli, Enrico; Lima, Annamaria; Valera, Paolo; De Vivo, Benedetto


    Characterization of risks to human health is determinant for risk management and population surveillance. This study represent the first work at national scale for Italy about arsenic occurrence, distribution and health impact. We analyzed the As geochemical distribution in different environmental matrices on the whole Italian territory, and assessed both carcinogenic and non-carcinogenic risks for different exposure routes and age groups. The results demonstrate that, in Italy, arsenic is present in significant concentrations both in water (up to 27.2 µg/L) and soils (up to 70 mg/kg). Its presence is mainly controlled by geological processes and locally reflects the industrial history of the Country. The population of the Central Italy, where high content of arsenic in the analyzed samples is due to the presence of alkaline volcanics, are the most exposed to the health risk. Based on the results of our work, it is clear that the consumption of tap water for potable use is the most impactful route for As daily exposure and play an important role in governing potential cancer and non-cancer risks for the considered population. It is interesting to observe that the Incremental Life Cancer Risk through water ingestion show that almost 80% of data falls above the internationally accepted benchmark value of 1 x 10-5. Moreover it was demonstrated that childhood is the most susceptible age stage to As exposure. Geochemical mapping provided a useful tool to spatially analyze and represent data and to highlight the most critic areas and the most exposed population to arsenic at national scale. In conclusion, this study improve knowledge about As occurrence for an entire Country, recognizing an health emerging problem. It might be a good starting point to support the urgently needed policy actions, in order to prevent and reduce the health risk. Moreover, the performed method in this case study research is potentially generalizable and applicable in other countries.

  3. "Suntelligence" Survey (United States)

    ... to the American Academy of Dermatology's "Suntelligence" sun-smart survey. Please answer the following questions to measure ... be able to view a ranking of major cities suntelligence based on residents' responses to this survey. ...

  4. Geochemical and isotopic characterization of groundwater discharge to the Athabasca River: Insights into sources of salinity (United States)

    Birks, S. J.; Moncur, M. C.; Gibson, J. J.; YI, Y.; Fennell, J.; Jasechko, S.


    The Athabasca Oil Sands Region (AOSR) of Northern Alberta represents an important oil reserve for Canada and the world. Identifying impacts of oil sands development to water quality requires indicators of anthropogenic impacts that can be clearly separated from natural background variability. Identifying suitable water quality parameters is complicated in this region because the Athabasca River and its tributaries are incised directly into bitumen saturated sands of the McMurray Formation, as well as other saline Cretaceous and Devonian Formations. Previous work has suggested that the natural input of saline groundwater from these formations may be the the cause for the large increases in chloride observed between Fort McMurray and Old Fort, but more detailed understanding the background inorganic and organic inputs from the different geological units along this stretch of the river will improve our understanding of the natural hydrogeochemical setting of the region and our ability to identify anthropogenic inputs. Here we compile and compare new isotope data collected from various seep sampling campaigns with regional groundwater and river water datasets to better understand the potential sources of dissolved solutes entering the Athabasca River from natural groundwater discharge. Geophysical surveys conducted along the Athabasca River were used to identify areas with elevated terrain conductivity where high salinity groundwater could be discharging to the river. Samples of porewater from the in the hyporheic zone in these areas were obtained using drive point piezometers installed between 1- 3m below the sediment interface. The porewater, groundwater and river water isotope data provide information about the sources of the water (δ18O and δ2H), and solutes (δ34S-SO4, 87Sr/86Sr, δ37Cl, δ11B, δ13C-DIC, δ13C-DOC) as well as information on groundwater ages (3H, 14C). The porewater in the alluvial sediment showed variable degrees of mixing with the overlying

  5. Fifth Anniversary of GEOCHIM 2003/UNESCO “Postgraduate certificated training course in geochemical exploration methods and their environmental applications”

    Institute of Scientific and Technical Information of China (English)



    It has been a tradition to organize very successful UNESCO Postgraduate Courses on Geochemical Prospecting Methods in the former Czechoslovakia from mid 70's. The first certificated course--GEOCHIM PRAHA UNESCO 1975 was launched on September 5, 1975 and lasted till October 25, 1975. Since that time this course has been organized biannually by the Czech Geological Survey in Prague together with the Dionyz Stur Geological Survey in Bratislava and sponsored by the Division of Earth Sciences (UNESCO/Paris) and the International Association of Geochemistry and Cosmochemistry (IAGS). The course was specialized on both theoretical and practical training in classical geochemical prospecting methods. A team of internationally experienced geoscientists as Drs.J.Pokorny, F.Mma, J.Manour, V.Lomozova Z. Sulcek,I. Rubeska, A.Spackova, V.Sixta, J.Juna,J.Veselu, J.Dornic and others, co-ordinated by Dr. Zdenek Pacal from the Czech Geological Survey in Prague has soon earned high international reputation and the GEOCHIM CSSR UNESCO Postgraduate Course developed into one of the most successful Postgraduate Training Programmes of UNESCO.

  6. Survey Says (United States)

    McCarthy, Susan K.


    Survey Says is a lesson plan designed to teach college students how to access Internet resources for valid data related to the sexual health of young people. Discussion questions based on the most recent available data from two national surveys, the Youth Risk Behavior Surveillance-United States, 2003 (CDC, 2004) and the National Survey of…

  7. Water-column geochemical anomalies associated with the remnants of a mega plume: A case study after CR-2003 hydrothermal event in Carlsberg Ridge, NW Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ray, D.; Mirza, I.H.; Prakash, L.S.; Kaisary, S.; Sarma, Y.V.B.; Rao, B.R.; Somayajulu, Y.K.; Drolia, R.K.; KameshRaju, K.A.

    to analyse certain geochemical aspects of a plume. The oxidative particulates make plume waters turbid and this turbidity in turn can be detected with optical sensors mounted on a CTD or attached to deep tow. The optical backscatter profiles along... below 2400 m, we restricted our water sampling mainly in deep (>2000 m) water. A Seabird CTD system (SBE 9/11 plus), bottle rosette along with light scattering sensors (WET Labs 633 and 634) was used for water-column survey. Water samples were...

  8. Do weirs affect the physical and geochemical mobility of toxic metals in mining-impacted floodplain sediments? (United States)

    Bulcock, Amelia; Coleman, Alexandra; Whitfield, Elizabeth; Andres Lopez-Tarazon, Jose; Byrne, Patrick; Whitfield, Greg


    aerial vehicle (UAV) photographic surveys, historical aerial photographs, ground-based topographic surveys, surface and subsurface particle size determination, bed stability and sediment entrainment assessment, together with discharge and sediment (both suspended and bedload) monitoring to establish the effect of the weir on patterns of sediment flux and the physical transport of metal contaminants. 2D and 1D models (IBER, HEC-RAS) of the weir-affected reach will investigate sediment and metal flux following weir removal. (2) The physicochemical speciation and geochemical stability of contaminated floodplain sediments will be characterised using bulk chemistry, mineralogical (XRD, SEM) and speciation methods (sequential extractions, electron microprobe analysis).

  9. An interactive code (NETPATH) for modeling NET geochemical reactions along a flow PATH, version 2.0 (United States)

    Plummer, L. Niel; Prestemon, Eric C.; Parkhurst, David L.


    NETPATH is an interactive Fortran 77 computer program used to interpret net geochemical mass-balance reactions between an initial and final water along a hydrologic flow path. Alternatively, NETPATH computes the mixing proportions of two to five initial waters and net geochemical reactions that can account for the observed composition of a final water. The program utilizes previously defined chemical and isotopic data for waters from a hydrochemical system. For a set of mineral and (or) gas phases hypothesized to be the reactive phases in the system, NETPATH calculates the mass transfers in every possible combination of the selected phases that accounts for the observed changes in the selected chemical and (or) isotopic compositions observed along the flow path. The calculations are of use in interpreting geochemical reactions, mixing proportions, evaporation and (or) dilution of waters, and mineral mass transfer in the chemical and isotopic evolution of natural and environmental waters. Rayleigh distillation calculations are applied to each mass-balance model that satisfies the constraints to predict carbon, sulfur, nitrogen, and strontium isotopic compositions at the end point, including radiocarbon dating. DB is an interactive Fortran 77 computer program used to enter analytical data into NETPATH, and calculate the distribution of species in aqueous solution. This report describes the types of problems that can be solved, the methods used to solve problems, and the features available in the program to facilitate these solutions. Examples are presented to demonstrate most of the applications and features of NETPATH. The codes DB and NETPATH can be executed in the UNIX or DOS1 environment. This report replaces U.S. Geological Survey Water-Resources Investigations Report 91-4078, by Plummer and others, which described the original release of NETPATH, version 1.0 (dated December, 1991), and documents revisions and enhancements that are included in version 2.0. 1 The

  10. Coupling R and PHREEQC: an interactive and extensible environment for efficient programming of geochemical models (United States)

    De Lucia, Marco; Kühn, Michael


    manipulations and visualization in a powerful high level language, and benefiting from an enormous amount of third-party open source R extensions. The possibility to rapidly prototype complex algorithms involving geochemical modelling is in our opinion a huge advantage. A demonstration is given by the successful evaluation of a strategy to reduce the CPU-time needed to perform reactive transport simulations in a sequential coupling scheme. The idea is the "reduction" of the number of actual chemical simulations to perform at every time step, by searching for "duplicates" of each chemical simulations in the grid: such comparison involves typically a huge number of elements (one chemical simulation for grid element for time step) and a quite large number of variables (concentrations and mineral abundances). However, through the straightforward implementation of the prototype algorithm through the R/PHREEQC interface, we found out that the scan is extremely cost-effective in terms of CPU-time and typically allows a relevant speedup for simulations starting from a homogeneous or zone-homogeneous state. This speedup can even greatily exceed that of parallelization in some favorable but not unfrequent case. This feature should therefore be implemented in reactive transport simulators. References [1] Parkhurst D, Appelo C (1999) Users guide to PHREEQC (version 2). Tech. rep, U.S. Geological Survey. [2] Beyer C, Li D, De Lucia M, Kühn M, Bauer S (2012): Modelling CO2-induced fluid-rock interactions in the Altensalzwedel gas reservoir. Part II: coupled reactive transport simulation. Environ. Earth Sci., 67, 2, 573-588. [3] R Core Team (2012) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL [4] Kühn M, Münch U (2012) CLEAN: CO2 Large-Scale Enhanced Gas Recovery. GEOTECHNOLOGIEN Science Report No. 19. Series: Advanced. Technologies in Earth Sciences, 199 p, ISBN 978-3-642-31676-0.

  11. Landscape and bio- geochemical strategy for monitoring transformation and reclamation of the soil mining sites (United States)

    Korobova, Elena


    Sites of active or abandoned mining represent areas of considerable technogenic impact and need scientifically ground organization of their monitoring and reclamation. The strategy of monitoring and reclamation depends on the scale and character of the physical, chemical and biological consequences of the disturbances. The geochemical studies for monitoring and rehabilitation of the career-dump complexes should methodically account of formation of the particular new landforms and the changes in circulation of the remobilized elements of the soil cover. However, the general strategy should account of both the initial and transformed landscape geochemical structure of the area with due regard to the natural and new content of chemical elements in the environmental components. For example the tailings and waste rocks present new geochemical fields with specifically different concentration of chemical elements that cause formation of new geochemical barriers and landscapes. The way of colonization of the newly formed landscapes depends upon the new geochemical features of the technogenic environment and the adaptive ability of local and intrusive flora. The newly formed biogeochemical anomalies need organization of permanent monitoring not only within the anomaly itself but also of its impact zones. Spatial landscape geochemical monitoring combined with bio-geochemical criteria of threshold concentrations seems to be a helpful tool for decision making on reclamation and operation of the soil mining sites to provide a long-term ecologically sustainable development of the impact zone as a whole.

  12. Modelling geochemical and microbial consumption of dissolved oxygen after backfilling a high level radiactive waste repository. (United States)

    Yang, Changbing; Samper, Javier; Molinero, Jorge; Bonilla, Mercedes


    Dissolved oxygen (DO) left in the voids of buffer and backfill materials of a deep geological high level radioactive waste (HLW) repository could cause canister corrosion. Available data from laboratory and in situ experiments indicate that microbes play a substantial role in controlling redox conditions near a HLW repository. This paper presents the application of a coupled hydro-bio-geochemical model to evaluate geochemical and microbial consumption of DO in bentonite porewater after backfilling of a HLW repository designed according to the Swedish reference concept. In addition to geochemical reactions, the model accounts for dissolved organic carbon (DOC) respiration and methane oxidation. Parameters for microbial processes were derived from calibration of the REX in situ experiment carried out at the Aspö underground laboratory. The role of geochemical and microbial processes in consuming DO is evaluated for several scenarios. Numerical results show that both geochemical and microbial processes are relevant for DO consumption. However, the time needed to consume the DO trapped in the bentonite buffer decreases dramatically from several hundreds of years when only geochemical processes are considered to a few weeks when both geochemical reactions and microbially-mediated DOC respiration and methane oxidation are taken into account simultaneously.

  13. Geochemical-Sequence Stratigraphy and Its Application Prospects in Lake Basins

    Institute of Scientific and Technical Information of China (English)

    李美俊; 纪云龙; 胡礼国


    As a useful approach for hydrocarbon exploration, the sequence stratigraphy has been commonly accepted. The concepts of sequence and parasequence provide a state-of-the-artframework for studying the distribution and characters of depositional system, and analyzing the occurrence, distribution, characteristics of source, reservoir and seal-play elements. The newly-de-veloped geochemical-sequence stratigraphy focuses mainly on the occurrence, distribution and characters of source rocks and reservoir hydrocarbons within a chronostratigraphic framework.Integrated with sequence stratigraphy, geochemistry can be used to study the source rock potential within a sequence stratigraphic framework and to describe the characteristics of hydrocarbons accumulated in reservoirs, which were predicted by way of sequence stratigraphy. The concept of geochemical-sequence stratigraphy was proposed by Peters et al. (2000). Constructing a reliable sequence stratigraphic framework is the basis of geochemical-sequence stratigraphic study although it is not the main goal. High-resolution biomarker analysis is critical to the construction of a geochemical-sequence stratigraphic model. The geochemical-stratigraphic study involves mainly: ( 1 ) the distribution and geochemical characteristics of source rocks within a sequence chronostratigraphic framework; (2) the geochemical features of source rocks with relative sea (lake)-level change; (3) to predict if these reservoirs bear hydrocarbons and their geochemical features; (4) to be used to construct the time-stratigraphic framework. This paper also summarizes the lake basin types, and introduces their facies associations, source potential and organic geochemical features. At the end, the authors offer some suggestions about how to carry out geo chemical-sequence stratigraphic study in lacustrine strata.

  14. Geochemical characteristics of Dongsheng sandstone-type uranium deposit, Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    SUN Yuzhuang; LIU Chiyang; DAI Shifeng; QIN Peng


    Generally, sandstone-type uranium deposits can be divided into three zones according to their redox conditions: oxidized zone, ore zone and reduced zone. The Dongsheng uranium deposit belongs to this type. In order to study its geochemical characteristics, 11 samples were taken from the three zones of the Dongsheng uranium deposit. Five samples of them were collected from the oxidized zone, four samples from the ore zone and two samples from the reduced zone. These samples were analyzed using organic and inorganic geochemical methods. The results of GC traces and ICP-MASS indicate that the three zones show different organic and inorganic geochemical characteristics.

  15. Precipitation of heavy metals from acid mine drainage and their geochemical modeling (United States)

    Petrilakova, Aneta; Balintova, Magdalena; Holub, Marian


    Geochemical modeling plays an increasingly vital role in a number of areas of geoscience, ranging from groundwater and surface water hydrology to environmental preservation and remediation. Geochemical modeling is also used to model the interaction processes at the water - sediment interface in acid mine drainage (AMD). AMD contains high concentrations of sulfate and dissolved metals and it is a serious environmental problem in eastern Slovakia. The paper is focused on comparing the results of laboratory precipitation of metal ions from AMD (the Smolnik creek, Slovakia) with the results obtained by geochemical modeling software Visual Minteq 3.0.

  16. Precipitation of heavy metals from acid mine drainage and their geochemical modeling

    Directory of Open Access Journals (Sweden)

    Petrilakova Aneta


    Full Text Available Geochemical modeling plays an increasingly vital role in a number of areas of geoscience, ranging from groundwater and surface water hydrology to environmental preservation and remediation. Geochemical modeling is also used to model the interaction processes at the water - sediment interface in acid mine drainage (AMD. AMD contains high concentrations of sulfate and dissolved metals and it is a serious environmental problem in eastern Slovakia. The paper is focused on comparing the results of laboratory precipitation of metal ions from AMD (the Smolnik creek, Slovakia with the results obtained by geochemical modeling software Visual Minteq 3.0.

  17. How to build stable geochemical reservoirs on Mars? (United States)

    Plesa, Ana-Catalina; Tosi, Nicola; Breuer, Doris


    To explain the complex thermo-chemical processes needed for the formation of distinct and stable geochemical reservoirs early in the thermo-chemical evolution of Mars, most geochemical studies argue that fractional crystallization of a global magma ocean may reproduce the isotopic characteristic of the SNCs [1, 2]. However, geodynamical models show that such scenario is difficult to reconcile with other observations like late volcanic activity and crustal density values as obtained from gravity and topography modelling [3, 4]. The stable density gradient, which establishes after the mantle overturn has completed, inhibits thermal convection. Albeit capable to provide stable reservoirs, this scenario suggests a conductive mantle after the overturn which on the one hand fails to sample deep regions of the mantle and on the other hand is clearly at odds with the volcanic history of Mars. This is best explained by assuming a convective mantle and partial melting as the principal agents responsible for the generation and evolution of Martian volcanism. Therefore, in this work an alternative scenario for the formation of early stable geochemical reservoirs is presented similar to the model of [5]. We investigate the influence of partial melting on mantle dynamics, crustal formation, and volcanic outgassing of a one-plate planet using a 2D mantle convection code. When melt is extracted to form crust, the mantle material left behind is more buoyant than its parent material and depleted in radioactive heat sources. The extracted heat-producing elements are then enriched in the crust, which also has an insulating effect due to its lower thermal conductivity compared to the mantle. In addition, partial melting can influence the mantle rheology through the dehydration (water depletion) of the mantle material by volcanic outgassing. As a consequence, the viscosity of water-depleted regions increases more than two orders of magnitude compared to water-saturated rocks resulting

  18. Geochemical characterization of tubular alteration features in subseafloor basalt glass (United States)

    Knowles, Emily; Staudigel, Hubert; Templeton, Alexis


    There are numerous indications that subseafloor basalts may currently host a huge quantity of active microbial cells and contain biosignatures of ancient life in the form of physical and chemical basalt glass alteration. Unfortunately, technological challenges prevent us from observing the formation and mineralization of these alteration features in situ, or reproducing tubular basalt alteration processes in the laboratory. Therefore, comprehensive analysis of the physical and chemical traces retained in mineralized tubules is currently the best approach for deciphering a record of glass alteration. We have used a number of high-resolution spectroscopic and microscopic methods to probe the geochemical and mineralogical characteristics of tubular alteration features in basalt glasses obtained from a suite of subseafloor drill cores that covers a range of different collection locations and ages. By combining three different synchrotron-based X-ray measurements - X-ray fluorescence microprobe mapping, XANES spectroscopy, and μ-XRD - with focused ion beam milling and transmission electron microscopy, we have spatially resolved the major and trace element distributions, as well as the oxidation state of Fe, determined the coordination chemistry of Fe, Mn and Ti at the micron-scale, and constrained the secondary minerals within these features. The tubular alteration features are characterized by strong losses of Fe2+, Mn2+, and Ca2+ compared to fresh glass, oxidation of the residual Fe, and the accumulation of Ti and Cu. The predominant phases infilling the alteration regions are Fe3+-bearing silicates dominated by 2:1 clays, with secondary Fe- and Ti-oxides, and a partially oxidized Mn-silicate phase. These geochemical patterns observed within the tubular alteration features are comparable across a diverse suite of samples formed over the past 5-100 Ma, which shows that the microscale mineralization processes are common and consistent throughout the ocean basins and

  19. The geochemical evolution of the Mt. Somma-Vesuvius volcano (United States)

    Paone, A.


    This work integrates new geochemical data with the numerous published analyses on rocks from the Mt. Somma-Vesuvius volcano. New quantitative models for the evolution of magma source regions and magma at different depths are proposed. The origin of the Somma-Vesuvius parental magma is modeled as 0.05-0.1 melt fractions of a MORB-type source composed of 54% olivine, 30% orthopyroxene, 10% clinopyroxene, 1% garnet, and 4% amphibole, and 1-5% sediment introduced through the adjacent arc system. The excess concentrations of Rb, Ba, K, and Sr are attributed to a subduction-related fluid phase. Major and trace element concentrations, coupled with Sr-Nd-Pb isotope signatures suggest that the bulk composition of sediments being subducted below southern Italy is similar to that of the carbonate rich sediment columns described by Plank and Langmuir (1998) and Vroon et al. (1995). Furthermore, it appears that the sediment contribution was introduced as a partial melt, which would account for some geochemical patterns, such as 143Nd/144Nd versus Th/Ce. The EC-AFC model ( Spera and Bohrson, 2001) is then used to track the evolution of Somma-Vesuvius magmas. The results are consistent with the melting of crustal Hercynian basement at depths of 12 and >20 km ( De Natale et al., 2001). Such a model is also consistent with the thermal model of Annen and Sparks (2002) for the evolution of magmatic provinces. Here, magmas from the upper mantle form a melt intrusion and storage zone at 12 to >20 km allowing for crustal melting to take place. At Vesuvius, Plinian eruptions involve the first magma withdrawn from a deep magma reservoir. Interplinian eruptions involve reduced volumes of magma stored over a larger depth range until the volcanic activity stops. This suggests that little magma is left in the melt intrusion and storage zone. A new cycle is started by a Plinian event when new magma rises from the upper mantle and is emplaced in the lower crust.

  20. Geochemistry of soils along a transect from Central Mexico to the Pacific Coast: a pilot study for continental-scale geochemical mapping (United States)

    Chiprés, J.A.; de la Calleja,; Tellez, J.I.; Jiménez, F.; Cruz, Carlos; Guerrero, E.G.; Castro, J.; Monroy, M.G.; Salinas, J.C.


    The Mexican Geological Survey (SGM), the National Institute of Statistics, Geography and Informatics (INEGI) and the Autonomous University of San Luis Potosi (UASLP) have established a multidisciplinary team with the objective of creating a national program of geochemical mapping of soils in Mexico. This is being done as part of the North American Soil Geochemical Landscapes Project in partnership with the US Geological Survey and the Geological Survey of Canada. As the first step, a pilot study was conducted over a transect that extends from the Mexico–US border near Ciudad Juarez in the north to the Pacific Ocean in the south. This pilot transect was conducted in two phases, and this paper presents results from the first phase, which sampled soils at about a 40-km spacing along a 730-km transect beginning in Central Mexico and ending at the Pacific Coast. Samples were collected from the A and C horizons at each site and 60 elements were analyzed. This pilot study demonstrates that geochemical mapping based on a 40-km spacing is adequate to identify broad-scale geochemical patterns. Geologic influence (i.e., soil parent material) was the most important factor influencing the distribution of elements along the transect, followed by the influence of regional mineralization. The study also showed that influence by human activities over the transect is minimal except possibly in large mining districts. A comparison of element abundance in the A horizon with the environmental soil guidelines in Mexico showed that the natural concentrations of the studied soils were lower than the established threshold for soil restoration with the exception of V and As. The former had a median value (75 mg/kg) approximately equal to the value established in Mexico for soil restoration in agricultural and residential lands (78 mg/kg), and the latter had three values higher than the 22 mg/kg threshold for soil restoration in agricultural and residential lands. These cases demonstrate

  1. The Role of Volcanic Sour Gas on the Alteration of Martian Basalt: Insights from Geochemical Modeling (United States)

    Berger, G.; Treguier, E.; D'Uston, C.; Pinet, P.; Toplis, M. J.


    We assess the chemical constraints of the alteration of basaltic material by a cold aqueous phase under atmospheric sour gas containing SO3. Secondary chemistry and mineralogy are calculated by a geochemical simulator and compared to MER data.


    Given the complexity of the various, simultaneous (and competing) equilibrium reactions governing the speciation of ionic species in aquatic systems, EPA has developed and distributed the geochemical speciation model MINTEQA2 (Brown and Allison, 1987, Allison et al., 1991; Hydrog...

  3. Establishing nursery estuary otolith geochemical tags for Sea Bass (Dicentrarchus labrax): Is temporal stability estuary dependent? (United States)

    Ryan, Diarmuid; Wögerbauer, Ciara; Roche, William


    The ability to determine connectivity between juveniles in nursery estuaries and adult populations is an important tool for fisheries management. Otoliths of juvenile fish contain geochemical tags, which reflect the variation in estuarine elemental chemistry, and allow discrimination of their natal and/or nursery estuaries. These tags can be used to investigate connectivity patterns between juveniles and adults. However, inter-annual variability of geochemical tags may limit the accuracy of nursery origin determinations. Otolith elemental composition was used to assign a single cohort of 0-group sea bass Dicentrarchus labrax to their nursery estuary thus establishing an initial baseline for stocks in waters around Ireland. Using a standard LDFA model, high classification accuracies to nursery sites (80-88%) were obtained. Temporal stability of otolith geochemical tags was also investigated to assess if annual sampling is required for connectivity studies. Geochemical tag stability was found to be strongly estuary dependent.

  4. Some geochemical characteristics of the Pachuca Obsidian Region: a strategy for interpreting artifact groups

    Energy Technology Data Exchange (ETDEWEB)

    Neivens, M.; Harbottle, G.; Kimberlin, J.


    Obsidian research has revealed geochemical anomalies. Neutron activation analysis was used to analyze the samples. Correlations were made between element pairs (Sc and Fe, Ba and Co). Tests were made for homogeneity. 5 figures. (DLC)

  5. Geochemical Characterization of Groundwater in a Volcanic System

    Directory of Open Access Journals (Sweden)

    Carmelo Bellia


    Full Text Available A geochemical investigation was undertaken at Mt. Etna Volcano to better define groundwater characteristics of its aquifers. Results indicate that the Na–Mg ± Ca–HCO3− ± (SO42− or Cl− type accounts for more than 80% of the groundwater composition in the volcano. The remaining 20% is characterized by elevated Ca2+. Waters along coastal areas are enriched in SO42− or Cl−, mainly due to mixing with seawater and anthropogenic effects. The majority of the samples showed values between −4‰ to −9‰ for δ18O and −19‰ to −53‰ for δ2H, suggesting that precipitation is the predominant source of recharge to the aquifers, especially in the west of the study area. The analysis of δ13C and pCO2 shows values 1 to 3 times higher than those expected for waters in equilibrium with the atmosphere, suggesting a partial gas contribution from deep sources. The diffusion of gasses is likely to be controlled by tectonic structures in the volcano. The ascent of deep brines is also reflected in the CO2 enrichment (up to 2.2 bars and enriched δ2H/δ18O compositions observed in the salt mounts of Paternò.

  6. Geochemical Energy for Catabolism and Anabolism in Hydrothermal Systems (United States)

    Amend, J. P.; McCollom, T. M.; Bach, W.


    Chemically reduced deep-sea vent fluids mixed with oxidized seawater can generate redox disequilibria that serve as energy sources for chemolithoautotrophic (catabolism) and biomass synthesis (anabolism) reactions. Numerical models can be used to evaluate Gibbs energies of such processes on the early Earth and in present-day systems. Here, geochemical data from compositionally diverse vent fluids (Lost City, Rainbow, Logatchev, TAG, 21 °N EPR) are combined with several seawater chemistries to yield a wide range of mixed hydrothermal solutions; this is the starting point for our thermodynamic calculations. In ultramafic-hosted hydrothermal systems, such as Rainbow or Lost City, aerobic chemolithotrophic catabolisms (oxidation of H2, FeII, CH4) are the most energy-yielding at low temperatures (catabolic reaction energetics can then be used to put constraints on the amount of primary biomass production. Under putative early Earth conditions, for example, the net chemoautotrophic synthesis of cellular building blocks is thermodynamically most favorable at moderate temperatures (~50°C), where the energy contributions from HCO3- and H+ in cool seawater coupled to the reducing power in hot vent fluid are optimized. At these conditions, and counter to conventional wisdom, the synthesis of amino acids may even yield small amounts of energy.

  7. Novorossiysk agglomeration landscapes and cement production: geochemical impact assessment (United States)

    Alekseenko, A. V.; Pashkevich, M. A.


    The article deals with assessing the environmental impact of marl mining and cement production in Novorossiysk city (Krasnodar krai, Russia). The existing methods of studying the environmental effects caused by the cement industry have been reviewed. Soil and aquatic vegetation sampling has been carried out and the gross concentration of metals in the samples has been defined. The research has been conducted in the certified and accredited laboratory using emission spectral analysis. The external control has been carried out via X-ray fluorescence analysis. Based on the collected data, main chemical pollutants in soil cover and water area near the cement plant have been identified. The contaminants released by urban enterprises and motor vehicle emissions, as well as fugitive dust from dumps and the cement factory, lead to multi-element lithogeochemical anomaly at geochemical barriers in soils. Accumulation of pollutants in soil depends on the type of land use and the area relief. The most contaminated aquatic landscapes have been identified in the inner bay. According to this information, the technical proposals can be prepared for environmental safety management in strongly polluted city areas, as well as for the reclamation design in the areas currently experiencing the negative impact of cement production.

  8. Petrologic and REE Geochemical Characters of Burnt Rocks

    Institute of Scientific and Technical Information of China (English)

    HUANG Lei; LIU Chiyang; YANG Lei; ZHAO Junfeng; FANG Jianjun


    The study of burnt rocks is beneficial to the discussion on the tectonic movement,paleoclimate and paleogeography that coal seams are subjected to after they were formed. In order to obtain the basic data on the features of the burnt rocks, a systematic study of petrology and REE geochemistry on burnt rocks in Shenmu, Northern Shaanxi Province has been done, using the methods of SEM, EDS, susceptibility measurements and ICP-MS. The burnt rocks are divided into two series in the section: the melted rocks and the baked rocks. SEM and EDS analyses reveal that all the minerals show burnt and melted traces, and there are no clay minerals except iliite found in the burnt rocks. Susceptibility measurements reveal that the burnt rocks have abnormally high susceptibility values,whereas a geochemical analysis shows that the REE distribution pattern of burnt rocks is similar to that of sedimentary rocks (initial rocks). In the longitudinal section, with increasing degree of burning (from baked rocks to melted rocks), the ΣREE gradually decreases, and the total REE of melted rocks is obviously lower than that of baked rocks. Besides, the melted rocks show apparent negative Ce anomalies, while the baked rocks show no anomaly of Ce, and sometimes even show positive anomalies.

  9. New geochemical investigations in Platanares and Azacualpa geothermal sites (Honduras) (United States)

    Barberi, Franco; Carapezza, Maria Luisa; Cioni, Roberto; Lelli, Matteo; Menichini, Matia; Ranaldi, Massimo; Ricci, Tullio; Tarchini, Luca


    Platanares and Azacualpa geothermal sites of Honduras are located in an inner part of the Caribbean Plate far from the active volcanic front of Central America. Here geology indicates that there are not the conditions for the occurrence of shallow magmatic heat sources for high-enthalpy geothermal resources. Geothermal perspectives are related to the possibility of a deep circulation of meteoric water along faults and the storage of the heated fluid in fractured permeable reservoirs. Geochemical geothermometers indicate a temperature for the deeper part of the geothermal reservoir close to 200 °C for Platanares and of 150-170 °C for Azacualpa. Calcite scaling, with subordinate silica deposition has to be expected in both sites. CO2 soil flux investigations have been carried out in both areas and reveal the presence of positive anomalies likely corresponding to the presence at depth of fractured degassing geothermal reservoirs. Compared with the geothermal areas of Central Italy whose reservoirs are hosted in carbonate rocks, e.g. Latera (Chiodini et al., 2007), the CO2 soil flux measured in Honduras is significantly lower (mean of 17 g/m2day at Platanares and of 163 g/m2day at Azacualpa) probably because of the dominant silicate nature of the deep reservoirs.

  10. Lagrangian simulation of mixing and reactions in complex geochemical systems (United States)

    Engdahl, Nicholas B.; Benson, David A.; Bolster, Diogo


    Simulations of detailed geochemical systems have traditionally been restricted to Eulerian reactive transport algorithms. This note introduces a Lagrangian method for modeling multicomponent reaction systems. The approach uses standard random walk-based methods for the particle motion steps but allows the particles to interact with each other by exchanging mass of their various chemical species. The colocation density of each particle pair is used to calculate the mass transfer rate, which creates a local disequilibrium that is then relaxed back toward equilibrium using the reaction engine PhreeqcRM. The mass exchange is the only step where the particles interact and the remaining transport and reaction steps are entirely independent for each particle. Several validation examples are presented, which reproduce well-known analytical solutions. These are followed by two demonstration examples of a competitive decay chain and an acid-mine drainage system. The source code, entitled Complex Reaction on Particles (CRP), and files needed to run these examples are hosted openly on GitHub (, so as to enable interested readers to readily apply this approach with minimal modifications.

  11. Microbiological and geochemical characterization of fluvially deposited sulfidic mine tailings (United States)

    Wielinga; Lucy; Moore; Seastone; Gannon


    The fluvial deposition of mine tailings generated from historic mining operations near Butte, Montana, has resulted in substantial surface and shallow groundwater contamination along Silver Bow Creek. Biogeochemical processes in the sediment and underlying hyporheic zone were studied in an attempt to characterize interactions consequential to heavy-metal contamination of shallow groundwater. Sediment cores were extracted and fractionated based on sediment stratification. Subsamples of each fraction were assayed for culturable heterotrophic microbiota, specific microbial guilds involved in metal redox transformations, and both aqueous- and solid-phase geochemistry. Populations of cultivable Fe(III)-reducing bacteria were most prominent in the anoxic, circumneutral pH regions associated with a ferricrete layer or in an oxic zone high in organic carbon and soluble iron. Sulfur- and iron-oxidizing bacteria were distributed in discrete zones throughout the tailings and were often recovered from sections at and below the anoxic groundwater interface. Sulfate-reducing bacteria were also widely distributed in the cores and often occurred in zones overlapping iron and sulfur oxidizers. Sulfate-reducing bacteria were consistently recovered from oxic zones that contained high concentrations of metals in the oxidizable fraction. Altogether, these results suggest a highly varied and complex microbial ecology within a very heterogeneous geochemical environment. Such physical and biological heterogeneity has often been overlooked when remediation strategies for metal contaminated environments are formulated.


    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, Eugene D.; Calvin, Kevin


    In recent years the search for life-forms at the earliest periods of geological time has been continued not only at the morphological level but also at the molecular level. This has been possible as a result of the increase in the biochemical knowledge and with the advent of analytical techniques that are capable of describing the intimate molecular architecture of individual molecules in acute detail. The fundamental premises upon which this organic geochemical approach rest are the following: that certain molecules, possessing a characteristic structural skeleton, show a reasonable stability to degradation over long periods of geological time; that their structural specificity can be understood in terms of known biosynthetic sequences; and that their formation by any non-biological means is of negligible probability. In this manuscript it is proposed to critically re-examine these premises and to establish criteria whereby one can differentiate molecules derived from biological systems from those that have their origin in non-biological processes. The importance of establishing such criteria lies in the significance these criteria have in determining whether life exists, or has existed, on other planets. Within the very near future it may be possible to provide an initial answer to this question when the first lunar samples are returned to the earth for analysis.

  13. Geochemical characteristics of Early Cretaceous source rocks in Boli Basin

    Institute of Scientific and Technical Information of China (English)

    Hongmei Gao; Fuhong Gao; Fu Fan; Yueqiao Zhang


    The Early Cretaceous deposits are composed of important source rocks in Boli Basin. The types of the source rocks include black mudstones and coal (with carbonaceous mudstone). By the organic geochemical analysis methods, the authors discussed the organic petrological characters, abundance of organic matter, degree of maturity and the type of source rocks. The main micro-component of black mudstone is exinite or vitrinite, and the content of vitrinite is high in coal. The weathering of the outcrop is very serious. The abundance of organic matter in source rock reaches the poor to better rank. The major kerogens in mudstone are type-Ⅲ, type-Ⅱ2 and some type-Ⅱ1; the organic type of coal is type-Ⅲ. The thermal evolution of the source rocks in every structural unit is very different, from low-maturity to over-maturity. The depositional environment is reductive, which is good for the preservation of organic matter. The organic matter in source rocks is mainly from aquatic organisms and terrigenous input.

  14. A geochemical and mineralogical approach to environmental protection

    Energy Technology Data Exchange (ETDEWEB)

    Memmi, I. [Siena Univ., Siena (Italy). Dipt. di Scienze della Terra; Hunziker, J.C. [UNIL BFSH-2 CH, Institut de Mineralogie, Lausanne (Switzerland); Panichi, C. [Consiglio Nazionale delle Ricerche, International Institute for Geothermal Research, Ghezzano, PI (Italy)


    Chemical pollution of the biospheric environment by human activity has become a problem of regional and global scale. There is no doubt that the contribution of geochemistry and mineralogy in defining the extent of this problem and estimating its long-term effects on life-forms is fundamental. Most of the environmental pollution problems arise from human activity associated with the exploitation and utilisation of the Earth's resources, involving minerals and fluids in some way. These problems include waste generated by mining activity, industrial, domestic, and nuclear waste. Particular problems can arise form the use of minerals and rocks in buildings and monuments. The relationship between minerals and human health represents a special case. Minerals can, on the one hand, create a problem; but, on the other hand, due to their peculiar structural properties of potentially hazardous and also useful minerals, capable of adsorbing or neutralizing any toxic, acid and undesirable components. Geochemistry can make important contributions in defining background concentrations, in mapping and accounting for dispersion patterns, in understanding the chemical interaction of pollutants with natural dissolved constituents and mineral matter, in estimating residence times and the extent to which geochemical processes will remove pollutants from the environment.

  15. Geochemical Characterization of Copper Tailings after Legume Revegetation

    Directory of Open Access Journals (Sweden)

    Justine Perry T. Domingo


    Full Text Available Knowledge on the geochemistry of mine tailings is important in understanding the challenges in establishing vegetation cover on tailings dumps and mined out areas. In this study, the mineralogy and trace element composition of copper tailings were examined. Two legume species, Calopogonium mucunoides and Centrosema molle, were utilized to investigate the possible effects of these plants in the geochemical development of mine tailings into soil-like material. The initial mineralogical and chemical analysis of the tailings samples indicated poor conditions for plant growth—minimal levels of major nutrients and organic matter as well as elevated copper concentrations. Despite these conditions, the two legume species exhibited good growth rates. Both legumes have likewise signif icantly reduced heavy metal concentrations in the tailings, indicating the possibility of metal hyperaccumulation in the plant tissue. The mineral composition has been retained even after revegetation; nevertheless, breakdown of primary minerals and subsequent formation of clay minerals were detected. These results provide insights on the transformation of toxic materials into habitable substrates for sustained plant growth.

  16. Geochemical controls on shale groundwaters: Results of reaction path modeling

    Energy Technology Data Exchange (ETDEWEB)

    Von Damm, K.L.; VandenBrook, A.J.


    The EQ3NR/EQ6 geochemical modeling code was used to simulate the reaction of several shale mineralogies with different groundwater compositions in order to elucidate changes that may occur in both the groundwater compositions, and rock mineralogies and compositions under conditions which may be encountered in a high-level radioactive waste repository. Shales with primarily illitic or smectitic compositions were the focus of this study. The reactions were run at the ambient temperatures of the groundwaters and to temperatures as high as 250/degree/C, the approximate temperature maximum expected in a repository. All modeling assumed that equilibrium was achieved and treated the rock and water assemblage as a closed system. Graphite was used as a proxy mineral for organic matter in the shales. The results show that the presence of even a very small amount of reducing mineral has a large influence on the redox state of the groundwaters, and that either pyrite or graphite provides essentially the same results, with slight differences in dissolved C, Fe and S concentrations. The thermodynamic data base is inadequate at the present time to fully evaluate the speciation of dissolved carbon, due to the paucity of thermodynamic data for organic compounds. In the illitic cases the groundwaters resulting from interaction at elevated temperatures are acid, while the smectitic cases remain alkaline, although the final equilibrium mineral assemblages are quite similar. 10 refs., 8 figs., 15 tabs.

  17. Tracing the geochemical evolution of alkaline Lake Van, Turkey (United States)

    Kwiecien, Ola; Viehberg, Finn; Plessen, Birgit; Litt, Thomas; Tillman Meyer, Felix


    Terminal Lake Van, the world's largest soda basin, is characterised by Na-CO3-Cl water chemistry (Reimer et al., 2008), salinity of ~22 ‰ and high pH of ~9.7. The sedimentary record of the lake goes ca. 600 ka back and documents major climatic events over that period (Stockhecke et al., 2014). Alas, the longevity of the basin does not mean that it persisted unchanged over such a long time. Information collected within the ICDP PALEOVAN project clearly suggests that upon its birth the chemistry of early Lake Van was very different from its modern alkaline equivalent. Here we document, by means of proxy data, the changes in water chemistry in a transforming basin. Results of lithological (Stockhecke et al., 2014) and micropaleontological (ostracod, gastropod and diatom assemblages) analysis, combined with geochemical data (δ18O, δ13C, Mg/Ca, Sr/Ca) obtained from the biogenic and authigenic carbonate fraction imply, that early Lake Van was a relatively shallow, fresh-to-brackish and, most probably, open basin. Sedimentological information points to tectonic factors rather than climatic changes responsible for closing the lake ca. 430 ka ago. Reimer, A., Landmann, G., Kempe, S., 2008. Lake Van, Eastern Anatolia, Hydrochemistry and History. Aquat. Geochemistry 15, 195-222. Stockhecke, M., Sturm, M., Brunner, I., Schmincke, H.-U., Sumita, M., Kipfer, R., Cukur, D., Kwiecien, O., Anselmetti, F.S., 2014. Sedimentary evolution and environmental history of Lake Van (Turkey) over the past 600 000 years. Sedimentology.

  18. Geochemical factors controlling free Cu ion concentrations in river water (United States)

    Rozan, Tim F.; Benoit, Gaboury


    Copper speciation was determined monthly at seven sites on four rivers in southern New England to understand which geochemical factors control free metal ion concentrations in river water. Samples were conventionally filtered (stripping voltammetry (DPASV) was used to quantify natural organic complexation and cathodic stripping square wave voltammetry (CSSWV) to measure directly both Cu sulfide complexes and total EDTA concentrations. The results showed both dissolved organic matter (DOM) and sulfide complexation dominate Cu speciation and control the concentrations of free ion. Free Cu2+ was calculated to be in the subnanomolar range for the majority of the year. Only in the winter months, when concentrations of DOM and metal sulfides complexes were at a minimum were free metal ions directly measurable by DPASV at low nanomolar concentrations. The extent of sulfide complexation appears to be dominated by the size of headwater marshes (upstream sampling sites) and by the amount of sewage treatment plant effluent (downstream sites). DOM complexation was related to the organic matter composition and followed model organic ligands. Indirect evidence suggests variations in river water pH and Ca2+ (metal competition) has only a minor role in Cu complexation. Measured concentrations of total EDTA suggest this synthetic ligand can control Cu speciation in some highly developed watersheds; however, competition from Ni (and possibly Fe) limits the extent of this complexation.

  19. Geochemical record of anthropogenic impacts on Lake Valencia, Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yunping [Environmental Geochemistry Group, Southeast Environmental Research Center, Florida International University, Miami, FL 33199 (United States); Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 (United States)], E-mail:; Jaffe, Rudolf [Environmental Geochemistry Group, Southeast Environmental Research Center, Florida International University, Miami, FL 33199 (United States); Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 (United States)


    Bulk geochemical parameters and organic matter biomarkers in a short, high resolution gravity core (Lake Valencia, Venezuela) were examined to reconstruct anthropogenic impacts on the lake's conditions. During the period of ca. 1840-1990, sedimentary organic matter was characterized by high contents of total organic C (TOC) and total N (TN), low TOC/TN values as well as relatively enriched {delta}{sup 13}C and {delta}{sup 15}N signals, suggesting a primary autochthonous (algae and macrophytes) organic matter origin. The occurrence of large amounts of C{sub 23} and C{sub 25} relative to C{sub 29} and C{sub 31}n-alkanes indicated substantial inputs from submerged/floating macrophytes. The variations of C{sub 32} 15-keto-ol, tetrahymanol, diploptene, C{sub 32} bishomohopanol, 2-methylhopane, dinosterol and isoarborinol concentrations over the investigated period record changes in the planktonic community structure, including Botryococcus braunii, bacteriavore ciliates, cyanobacteria, Eustigmatophytes and dinoflagellates. A principal shift occurred in the 1910s when cyanobacteria and dinoflagellates became more abundant at the expense and decline of B. braunii and Eustigmatophytes, likely related to increasing anthropogenic activity around the lake. A second shift (less obvious) occurred in the 1960s when cyanobacteria became the sole predominant planktonic class, coinciding with further deterioration of lake conditions.

  20. Geochemical effects of electro-osmosis in clays

    KAUST Repository

    Loch, J. P. Gustav


    Geochemical effects of electro-osmosis in bentonite clay are studied in the laboratory, where a 6 mm thick bentonite layer is subjected to direct current. Acidification and alkalization near anode and cathode are expected, possibly causing mineral deterioration, ion mobilization and precipitation of new solids. Afterwards the clay is analysed by XRF and anolyte and catholyte are analysed by ICP-MS. In addition, as a preliminary experiment treated bentonite is analysed by high resolution μ-XRF. Electro-osmotic flow is observed. Due to its carbonate content the bentonite is pH-buffering. Alkalization in the catholyte is substantial. Ca, Na and Sr are significantly removed from the clay and accumulate in the catholyte. Recovery in the catholyte accounts for a small fraction of the element-loss from the clay. The rest will have precipitated in undetected solid phases. μ-XRF indicates the loss of Ca-content throughout the bentonite layer. © The Author(s) 2010.

  1. GEMAS: Geochemical Distribution of Thallium in European Soil (United States)

    Demetriades, Alecos; Birke, Manfred; Reimann, Clemens; Mann, Alan; Kaminari, Maria


    Thallium concentrations are reported for the Vesuvius, Campi Felgrei and Mount Vulture); similar anomalous patterns are shown by Be, Pd and Pt. Most granitic intrusions are also marked by high Tl values (e.g., northern Portugal, Massif Central in France, and Bohemian Massif in Czechia). The median Tl concentration of Ap soil samples in the mobile metal ion (MMI®) partial extraction is 0.0006 mg/kg, and almost 50% of all samples report concentrations below detection. There is no pronounced difference between northern and southern Europe anymore, and the ice age limit of the last glaciation remains invisible. The main anomaly is related to the alkaline volcanic rocks in Italy. Many granitic intrusions are indicated by somewhat enhanced Tl concentrations (e.g., northern Portugal, north-western Spain, Massif Central in France, south-west England, and Bohemian Massif in Czechia). An interesting NE to SW anomalous pattern occurs in Scotland, partly following the Great Glen fault, and occurrences of granitic intrusions. Almost all of central Europe is marked by enhanced Tl values, and one wonders whether agriculture might have had an impact on this unusual pattern. Finally, the GEMAS data set defines the geochemical background variation of Tl in aqua regia and MMI® extraction for European agricultural and grazing land soil at the 2008 timeline.

  2. Reservoir simulation and geochemical study of Cerro Prieto I wells

    Energy Technology Data Exchange (ETDEWEB)

    Lippmann, M.J. (Lawrence Berkeley Lab., CA (USA)); Truesdell, A.H. (Geological Survey, Menlo Park, CA (USA))


    Combined reservoir simulation and geochemical data analysis are used to investigate the effects of recharge and other reservoir processes occurring in the western part of the Cerro Prieto, Mexico, geothermal field (i.e., Cerro Prieto I area). Enthalpy-based temperatures and bottomhole temperatures are calculated based on simplified models of the system, considering different reservoir boundary conditions and zones of contrasting initial temperatures and reservoir properties. By matching the computed trends with geothermometer-based temperature and enthalpy histories of producing wells, the main processes active in the western area of Cerro Prieto are identified. This part of the geothermal system is strongly influenced by nearby groundwater aquifers; cooler waters readily recharge the reservoirs. In response to exploitation, the natural influx of cold water into the shallower alpha reservoir is mainly from the west and down Fault L, while the recharge to the deeper beta reservoir in this part of the field, seems to be only lateral, from the west and possibly south. 11 refs., 12 figs.

  3. Assessment Cu, Ni and Zn Pollution in the Surface Sediments in the Southern Peninsular Malaysia using Cluster Analysis, Ratios of Geochemical Nonresistant to Resistant Fractions, and Geochemical Indices


    Yap. C. K.


    The intertidal sediment samples collected in May 2007 from 12 sampling sites in the southern part of Peninsular Malaysia, were determined for the total concentrations of Cu, Ni and Zn and their four geochemical fractions. The total concentrations (μg/g dry weight) of Cu, Ni and Zn ranged from 9.48 to 115.82, 12.95 to 36.18 and 45.35 to 136.56, respectively. The ratios of nonresistant to resistant fractions based on geochemical analysis revealed that the Pantai Lido and Senibong had > 1.0, ind...

  4. Environmental and geochemical assessment of surface sediments on irshansk ilmenite deposit area

    Directory of Open Access Journals (Sweden)

    Наталия Олеговна Крюченко


    Full Text Available It is revealed the problem of pollution of surface sediments of Irshansk ilmenite deposit area of various chemical elements hazard class (Mn, V, Ba, Ni, Co, Cr, Mo, Cu, Pb, Zn. It is determined its average content in surface sediments of various functional areas (forest and agricultural land, flood deposits, reclaimed land, calculated geochemical criteria, so given ecological and geochemical assessment of area

  5. A Guide for Using Geochemical Methods in Dredged Material, Sediment Tracking, and Sediment Budget Studies (United States)


    ER D C TR -1 7- 3 Dredging Operations and Environmental Research Program A Guide for Using Geochemical Methods in Dredged Material...Jennifer M. Seiter, Mark A . Chappell, and Brandon Lafferty June 2017 Approved for public release; distribution is unlimited. The U.S. Army...June 2017 A Guide for Using Geochemical Methods in Dredged Material, Sediment Tracking, and Sediment Budget Studies Heidi M. Wadman Coastal and

  6. Precipitation of heavy metals from acid mine drainage and their geochemical modeling


    Petrilakova Aneta; Balintova Magdalena; Holub Marian


    Geochemical modeling plays an increasingly vital role in a number of areas of geoscience, ranging from groundwater and surface water hydrology to environmental preservation and remediation. Geochemical modeling is also used to model the interaction processes at the water - sediment interface in acid mine drainage (AMD). AMD contains high concentrations of sulfate and dissolved metals and it is a serious environmental problem in eastern Slovakia. The paper is focused on comparing the results o...

  7. The application of fuzzy decision-making in geochemical data processing (United States)

    Zhou, Lili; Song, Liangtu; Liu, Lei; Wu, Yue


    Fuzzy similarity ratio method is a widely used method of fuzzy decision-making, not only to classification, but also to sort. In this paper, we constructed a geochemical anomaly evaluation model using the Fuzzy similarity ratio method; we also program it with C# language and applied the model to practical work. Practice has proved that the fuzzy decision-making applies to the evaluation of geochemical anomalies can effectively improve the accuracy of the evaluation.

  8. A new method for geochemical anomaly separation based on the distribution patterns of singularity indices (United States)

    Liu, Yue; Zhou, Kefa; Cheng, Qiuming


    Singularity analysis is one of the most important models in the fractal/multifractal family that has been demonstrated as an efficient tool for identifying hybrid distribution patterns of geochemical data, such as normal and multifractal distributions. However, the question of how to appropriately separate these patterns using reasonable thresholds has not been well answered. In the present study, a new method termed singularity-quantile (S-Q) analysis was proposed to separate multiple geochemical anomaly populations based on integrating singularity analysis and quantile-quantile plot (QQ-plot) analysis. The new method provides excellent abilities for characterizing frequency distribution patterns of singularity indices by plotting singularity index quantiles vs. standard normal quantiles. From a perspective of geochemical element enrichment processes, distribution patterns of singularity indices can be evidently separated into three groups by means of the new method, corresponding to element enrichment, element generality and element depletion, respectively. A case study for chromitite exploration based on geochemical data in the western Junggar region (China), was employed to examine the potential application of the new method. The results revealed that the proposed method was very sensitive to the changes of singularity indices with three segments when it was applied to characterize geochemical element enrichment processes. And hence, the S-Q method can be considered as an efficient and powerful tool for separating hybrid geochemical anomalies on the basis of statistical and inherent fractal/multifractal properties.

  9. [Study on geochemical susceptivity of groundwater system in representative karstic regions]. (United States)

    He, Shou-yang; Zhu, Li-jun; Dong, Zhi-fen; Zhang, Yi; Yu, Xiao-hong


    We investigated geochemical susceptivity of groundwater in representative karst groundwater system. The results indicated that Ca2+ and Mg2+, correlative the average values of geochemical susceptivity index (GSI) were 0.73 and 0.19; HCO3- and SO4(2-), interrelated the average values of geochemical susceptivity index were 0.92 and 0.37, are the principal cations and anions in karstic groundwater system, respectively. And the major elements are obviously characterized by the geochemical susceptivity. The rank order of geochemical susceptivity for major elements in study region is HCO3- > Ca2+ > SO4(2+) > Mg2+ > Cl- > Na+ > NO3- > K+. The susceptive regions of groundwater system were zoned by the geochemical susceptivity index of HCO3- (GSI(HCO3-)), which classified as GSI(HCO3-) 1 is high-susceptivity zone, respectively. The groundwater systems in high-susceptivity zone may become as a collected and genetic room for pollutants. Furthermore, both continual or active exchange and mutual recharge between surface water and groundwater in high-susceptivity zones might induce intersectant pollution and serious cycle.

  10. Geochemical signature of land-based activities in Caribbean coral surface samples (United States)

    Prouty, N.G.; Hughen, K.A.; Carilli, J.


    Anthropogenic threats, such as increased sedimentation, agrochemical run-off, coastal development, tourism, and overfishing, are of great concern to the Mesoamerican Caribbean Reef System (MACR). Trace metals in corals can be used to quantify and monitor the impact of these land-based activities. Surface coral samples from the MACR were investigated for trace metal signatures resulting from relative differences in water quality. Samples were analyzed at three spatial scales (colony, reef, and regional) as part of a hierarchical multi-scale survey. A primary goal of the paper is to elucidate the extrapolation of information between fine-scale variation at the colony or reef scale and broad-scale patterns at the regional scale. Of the 18 metals measured, five yielded statistical differences at the colony and/or reef scale, suggesting fine-scale spatial heterogeneity not conducive to regional interpretation. Five metals yielded a statistical difference at the regional scale with an absence of a statistical difference at either the colony or reef scale. These metals are barium (Ba), manganese (Mn), chromium (Cr), copper (Cu), and antimony (Sb). The most robust geochemical indicators of land-based activities are coral Ba and Mn concentrations, which are elevated in samples from the southern region of the Gulf of Honduras relative to those from the Turneffe Islands. These findings are consistent with the occurrence of the most significant watersheds in the MACR from southern Belize to Honduras, which contribute sediment-laden freshwater to the coastal zone primarily as a result of human alteration to the landscape (e.g., deforestation and agricultural practices). Elevated levels of Cu and Sb were found in samples from Honduras and may be linked to industrial shipping activities where copper-antimony additives are commonly used in antifouling paints. Results from this study strongly demonstrate the impact of terrestrial runoff and anthropogenic activities on coastal water

  11. Engineering surveying

    CERN Document Server

    Schofield, W


    The aim of Engineering Surveying has always been to impart and develop a clear understanding of the basic topics of the subject. The author has fully revised the book to make it the most up-to-date and relevant textbook available on the subject.The book also contains the latest information on trigonometric levelling, total stations and one-person measuring systems. A new chapter on satellites ensures a firm grasp of this vitally important topic.The text covers engineering surveying modules for civil engineering students on degree courses and forms a reference for the engineering surveying module in land surveying courses. It will also prove to be a valuable reference for practitioners.* Simple clear introduction to surveying for engineers* Explains key techniques and methods* Details reading systems and satellite position fixing

  12. Geologic Field Notes, Geochemical Analyses, and Field Photographs of Outcrops and Rock Samples from the Big Delta B-1 Quadrangle, East-Central Alaska (United States)

    Day, Warren C.; O'Neill, J. Michael


    The U.S. Geological Survey, in cooperation with the Alaska Department of Natural Resources Division of Mining, Land, and Water, has released a geologic map of the Big Delta B-1 quadrangle of east-central Alaska (Day and others, 2007). This companion report presents the major element oxide and trace element geochemical analyses, including those for gold, silver, and base metals, for representative rock units and for grab samples from quartz veins and mineralized zones within the quadrangle. Also included are field station locations, field notes, structural data, and field photographs based primarily on observations by W.C. Day with additions by J.M. O'Neill and B.M. Gamble, all of the U.S. Geological Survey. The data are provided in both Microsoft Excel spread sheet format and as a Microsoft Access database.


    Energy Technology Data Exchange (ETDEWEB)

    Millings, M.; Denham, M.; Looney, B.


    From the 1950s through 1989, the F Area Seepage Basins at the Savannah River Site (SRS) received low level radioactive wastes resulting from processing nuclear materials. Discharges of process wastes to the F Area Seepage Basins followed by subsequent mixing processes within the basins and eventual infiltration into the subsurface resulted in contamination of the underlying vadose zone and downgradient groundwater. For simulating contaminant behavior and subsurface transport, a quantitative understanding of the interrelated discharge-mixing-infiltration system along with the resulting chemistry of fluids entering the subsurface is needed. An example of this need emerged as the F Area Seepage Basins was selected as a key case study demonstration site for the Advanced Simulation Capability for Environmental Management (ASCEM) Program. This modeling evaluation explored the importance of the wide variability in bulk wastewater chemistry as it propagated through the basins. The results are intended to generally improve and refine the conceptualization of infiltration of chemical wastes from seepage basins receiving variable waste streams and to specifically support the ASCEM case study model for the F Area Seepage Basins. Specific goals of this work included: (1) develop a technically-based 'charge-balanced' nominal source term chemistry for water infiltrating into the subsurface during basin operations, (2) estimate the nature of short term and long term variability in infiltrating water to support scenario development for uncertainty quantification (i.e., UQ analysis), (3) identify key geochemical factors that control overall basin water chemistry and the projected variability/stability, and (4) link wastewater chemistry to the subsurface based on monitoring well data. Results from this study provide data and understanding that can be used in further modeling efforts of the F Area groundwater plume. As identified in this study, key geochemical factors

  14. Predictive Analysis of Geochemical Controls in an Alpine Stream (United States)

    Jochems, A. P.; Sherson, L. R.; Crossey, L. J.; Karlstrom, K. E.


    Alpine watersheds are increasingly relied upon for use in the American West, necessitating a more complete understanding of annual hydrologic patterns and geologic influences on water chemistry. The Jemez River is a fifth order stream in central New Mexico that flows from its source in the Jemez Mountains to its confluence with the Rio Grande north of the town of Bernalillo. Designated uses of the Jemez River include domestic water supply, recreation, and agriculture. Geothermal uses are currently being considered as well. The river recharges shallow aquifer waters used by several communities, including tribal lands of the Jemez Pueblo. The hydrogeology of the Jemez system is characterized by geothermal inputs from the Baca hydrothermal system associated with the 1.2Ma Valles caldera, as well as groundwater and surface water interactions. Freshwater input from the Rio Guadalupe and several ephemeral tributaries also influences the water chemistry of the Jemez system. Fifteen sites along a 35 km reach of the river were sampled between 2006 and 2010. Discharge of the Jemez River ranged from 10-876 cfs over the study period. The annual hydrograph is affected by annual snowmelt in the Jemez Mountains as well as surges due to monsoonal rains in July and August. Geochemical data collected over this period include temperature, conductivity, pH, dissolved oxygen (D.O.), major ions, trace elements, and stable isotopes. Continuous records of temperature, conductivity, pH, D.O. and turbidity data were collected from a water quality sonde installed in March 2010. Geochemical modeling and time series analysis were performed using PHREEQC, Geochemist’s Workbench, and MATLAB. Empirical data collected during this study gave rise to several models describing the hydrology and geochemistry of the Jemez system. Our data suggest that springs are the primary contributors to dissolved load, and that solute loading from geothermal inputs is intensified by low flows observed on

  15. The structure of a hydrothermal system from an integrated geochemical, geophysical, and geological approach: The Ischia Island case study (United States)

    di Napoli, R.; Martorana, R.; Orsi, G.; Aiuppa, A.; Camarda, M.; de Gregorio, S.; Gagliano Candela, E.; Luzio, D.; Messina, N.; Pecoraino, G.; Bitetto, M.; de Vita, S.; Valenza, M.


    The complexity of volcano-hosted hydrothermal systems is such that thorough characterization requires extensive and interdisciplinary work. We use here an integrated multidisciplinary approach, combining geological investigations with hydrogeochemical and soil degassing prospecting, and resistivity surveys, to provide a comprehensive characterization of the shallow structure of the southwestern Ischia's hydrothermal system. We show that the investigated area is characterized by a structural setting that, although very complex, can be schematized in three sectors, namely, the extra caldera sector (ECS), caldera floor sector (CFS), and resurgent caldera sector (RCS). This contrasted structural setting governs fluid circulation. Geochemical prospecting shows, in fact, that the caldera floor sector, a structural and topographic low, is the area where CO2-rich (>40 cm3/l) hydrothermally mature (log Mg/Na ratios 150 g m-2 d-1), is clearly captured by electrical resistivity tomography (ERT) and transient electromagnetic (TEM) surveys as a highly conductive (resistivity 10,000 mg/l) and poorly conductive meteoric-derived (TDS Ischia's hydrothermal system.

  16. Soil gas geochemical behaviour across buried and exposed faults during the 24 august 2016 central Italy earthquake

    Directory of Open Access Journals (Sweden)

    Giancarlo Ciotoli


    Full Text Available Following the earthquake (ML=6.0 of 24 August 2016 that affected large part of the central Apennine between the municipalities of Norcia (PG and Amatrice (RI (central Italy, two soil gas profiles (i.e., 222Rn, 220Rn, CO2 and CO2 flux were carried out across buried and exposed coseismic fault rupture of the Mt. Vettore fault during the seismic sequence. The objective of the survey was to explore the mechanisms of migration and the spatial behaviour of different gas species near still-degassing active fault. Results provide higher gas and CO2 flux values (about twice for 222Rn and CO2 flux in correspondence of the buried sector of the fault than those measured across the exposed coseismic rupture. Anomalous peaks due to advective migration are clearly visible on both side of the buried fault (profile 1, whereas the lower soil gas concentrations measured across the exposed coseimic rupture (profile 2 are mainly caused by shallow and still acting diffusive degassing associated to faulting during the seismic sequence. These results confirm the usefulness of the soil gas survey to spatially recognise the shallow geometry of hidden faults, and to discriminate the geochemical migration mechanisms occurring at buried and exposed faults related to seismic activity.

  17. A geochemical perspective on charnockite magmatism in Peninsular India

    Directory of Open Access Journals (Sweden)

    H.M. Rajesh


    Full Text Available Large charnockite massifs occur in the high-grade Southern Granulite Terrain (SGT and Eastern Ghats Belt (EGB crustal provinces of Peninsular India. Available geochronological data indicate that the magmatism is episodic, associated with distinct orogenic cycles in the different crustal domains. The geochemical data also indicate a change in composition from trondhjemitic at ∼3.0–2.9 Ga to dominantly tonalitic at ∼2.6–2.5 Ga to tonalitic-granodiorite-granitic at ∼2.0–1.9 Ga to dominantly tonalitic at 1.7–1.6 Ga to quartz monzonitic or tonalitic at ∼1.0–0.9 Ga to granodiorite-granitic at ∼0.8–0.7 Ga. The trondhjemitic and tonalitic end members are metaluminous, magnesian and calcic to calc-alkalic, characteristic of magnesian group charnockites. The granodioritic to granitic end members are metaluminous to slightly peraluminous, ferroan and calc-alkalic to alkali-calcic, characteristic of ferroan group charnockites. The quartz monzonitic end members are metaluminous to peraluminous, magnesian to ferroan and calcic to calc-alkalic, neither characteristic of the magnesian group nor of the ferroan group of charnockites. Based on the occurrence and difference in composition of the charnockite massifs, it is suggested that the charnockite magmatism registers the crustal growth of the Indian plate on its southern (SGT and eastern (EGB sides, along active continental margins by accretion of arcs.

  18. Geochemical tracers to evaluate hydrogeologic controls on river salinization. (United States)

    Moore, Stephanie J; Bassett, R L; Liu, Beiling; Wolf, Christopher P; Doremus, Dale


    The salinization of rivers, as indicated by salinity increases in the downstream direction, is characteristic of arid and semiarid regions throughout the world. Historically, salinity increases have been attributed to various mechanisms, including (1) evaporation and concentration during reservoir storage, irrigation, and subsequent reuse; (2) displacement of shallow saline ground water during irrigation; (3) erosion and dissolution of natural deposits; and/or (4) inflow of deep saline and/or geothermal ground water (ground water with elevated water temperature). In this study, investigation of salinity issues focused on identification of relative salinity contributions from anthropogenic and natural sources in the Lower Rio Grande in the New Mexico-Texas border region. Based on the conceptual model of the system, the various sources of water and, therefore, salinity to the Lower Rio Grande were identified, and a sampling plan was designed to characterize these sources. Analysis results for boron (delta(11)B), sulfur (delta(34)S), oxygen (delta(18)O), hydrogen (delta(2)H), and strontium ((87)Sr/(86)Sr) isotopes, as well as basic chemical data, confirmed the hypothesis that the dominant salinity contributions are from deep ground water inflow to the Rio Grande. The stable isotopic ratios identified the deep ground water inflow as distinctive, with characteristic isotopic signatures. These analyses indicate that it is not possible to reproduce the observed salinization by evapotranspiration and agricultural processes alone. This investigation further confirms that proper application of multiple isotopic and geochemical tracers can be used to identify and constrain multiple sources of solutes in complex river systems.

  19. A geochemical assessment of possible lunar ore formation (United States)

    Haskin, Larry A.; Colson, Russell O.; Vaniman, David

    The Moon apparently formed without appreciable water or other relatively volatile materials. Interior concentrations of water or other volatile substances appear to be extremely low. On Earth, water is important to the genesis of nearly all types of ores. Thus, some have reasoned that only abundant elements would occur in ore concentrations. The definition and recognition of ores on the Moon challenge the imaginations and the terrestrial perceptions of ore bodies. Lunar ores included solar-wind soaked soils, which contain abundant but dilute H, C, N, and noble gases (including He-3). Oxygen must be mined; soils contain approximately 45 percent (wt). Mainstream processes of rock formation concentrated Si, Mg, Al, Fe, and Ca, and possibly Ti and Cr. The highland surface contains approximately 70 percent (wt) feldspar (mainly CaAl2Si2O8), which can be separated from some highland soils. Small fragments of dunite were collected; dunite may occur in walls and central peaks of some craters. Theoretical extensions of observations of lunar samples suggest that the Moon may have produced ores of trace elements. Some small fragments have trace-element concentrations 104 times higher than the lunar average, indicating that effective geochemical separations occurred; processes included fractional crystallization, silicate immiscibility, vaporization and condensation, and sulfide metamorphism. Operations of these processes acting on indigenous materials and on meteoritic material in the regolith could have produced ores. Infalling carbonaceous meteorites and comets have added water and hydrocarbons that may have been cold-trapped. Vesicles in basalts, pyroclastic beads, and reported transient events suggest gag emission from the lunar interior; such gas might concentrate and transport rare elements. Large impacts may disperse ores or produce them through deposition of heat at depth and by vaporization and subsequent condensation. The main problem in assessing lunar resources is

  20. Geochemical Fate and Transport of Sildenafil and Vardenafil (United States)

    Richter, L.; Boudinot, G.; Vulava, V. M.; Cory, W. C.


    The geochemical fate of pharmaceuticals and their degradation products is a developing environmental field. The geologic, chemical, and biological fate of these pollutants has become very relevant with the increase in human population and the resulting increase in pollutant concentrations in the environment. In this study, we focus on sildenafil (SDF) and vardenafil (VDF), active compounds in Viagra and Levitra, respectively, two commonly used erectile dysfunction drugs. The main objective is to determine the sorption potential and transport behavior of these two compounds in natural soils. Both SDF and VDF are complex organic molecules with multiple amine functional groups in their structures. Two types of natural acidic soils (pH≈4.5), an organic-rich soil (7.6% OM) and clay-rich soil (5.1% clay) were used in this study to determine which soil components influence sorption behavior of both compounds. Sorption isotherms measured using batch reactors were nearly linear, but sorption was stronger in soil that contained higher clay content. Both compounds have multiple pKas due to the amine functional groups, the relevant pKas of SDF are 5.97 and 7.27, and those of VDF's are 4.72 and 6.21. These values indicate that these compounds likely behave as cations in soil suspensions and hence were strongly sorbed to negatively-charged clay minerals present in both soils. The clay composition in both soils is predominantly kaolinite with smaller amount of montmorillonite, both of which have a predominantly negative surface charge. Transport experiments using glass chromatography columns indicated that both compounds were more strongly retarded in the clay-rich soils. Breakthrough curves from the transport experiments were modeled using convection-dispersion transport equations. The organic matter in the soil seemed to play a less dominant role in the geochemistry in this study, but is likely to transform both compounds into derivative compounds as seen in other studies.

  1. Subglacial (bio)geochemical weathering and the unexplored Antarctic system (United States)

    Mitchell, A. C.; Christner, B. C.; Mikucki, J.; Priscu, J. C.


    the importance of subglacial hydrological-geochemical-microbiological interactions in the past, and in the future, at glacial-interglacial timescales.

  2. Origin of geochemical mantle components: Role of subduction filter (United States)

    Kimura, Jun-Ichi; Gill, James B.; Skora, Susanne; van Keken, Peter E.; Kawabata, Hiroshi


    We quantitatively explore element redistribution at subduction zones using numerical mass balance models to evaluate the roles of the subduction zone filter in the Earth's geochemical cycle. Our models of slab residues after arc magma genesis differ from previous ones by being internally consistent with geodynamic models of modern arcs that successfully explain arc magma genesis and include element fluxes from the dehydration/melting of each underlying slab component. We assume that the mantle potential temperature (Tp) was 1400-1650°C at 3.5-1.7 Ga and gradually decreased to 1300-1350°C today. Hot subduction zones with Tp ˜1650°C have a thermal structure like modern SW Japan where high-Mg andesite is formed which is chemically like continental crust. After 2.5-1.7 Gyr of storage in the mantle, the residual igneous oceanic crust from hot subduction zones can evolve isotopically to the HIMU mantle component, the residual base of the mantle wedge to EMI, the residual sediment becomes an essential part of EMII, and the residual top of the mantle wedge can become the subcontinental lithosphere component. The Common or Focal Zone component is a stable mixture of the first three residues occasionally mixed with early depleted mantle. Slab residues that recycled earlier (˜2.5 Ga) form the DUPAL anomaly in the southern hemisphere, whereas residues of more recent recycling (˜1.7 Ga) underlie the northern hemisphere. These ages correspond to major continental crust forming events. The east-west heterogeneity of the depleted upper mantle involves subcontinental mantle except in the Pacific.

  3. Geochemical Fate and Transport of Diphenhydramine and Cetirizine in Soil (United States)

    Wireman, R.; Rutherford, C. J.; Vulava, V. M.; Cory, W. C.


    Pharmaceuticals compounds presence in natural soils and water around the world has become a growing concern. These compounds are being discharged into the environment through treated wastewater or municipal sludge applications. The main goal of this study is determine their geochemical fate in natural soils. In this study we investigated sorption and transport behavior of diphenhydramine (DPH) and cetirizine (CTZ) in natural soils. These two commonly-used antihistamines are complex aromatic hydrocarbons with polar functional groups. Two clean acidic soils (pH~4.5) were used for these studies - an A-horizon soil that had higher organic matter content (OM, 7.6%) and a B-horizon soil that had lower OM (1.6%), but higher clay content (5.1%). Sorption isotherms were measured using batch reactor experiments. Data indicated that sorption was nonlinear and that it was stronger in clay-rich soils. The pKa's of DPH and CTZ are 8.98 and 8.27 respectively, i.e., these compounds are predominantly in cationic form at soil pH. In these forms, they preferentially sorb to negatively charged mineral surfaces (e.g., clay) present in the soils. Soil clay mineral characterization indicated that kaolinite was the dominant clay mineral present along with small amount of montmorillonite. The nonlinear sorption isotherms were fitted with Freundlich model. Transport behavior of both compounds was measured using glass chromatography columns. As expected both DPH and CTZ were strongly retained in the clay-rich soil as compared with OM-rich soil. The asymmetrical shape of the breakthrough curves indicated that there were likely two separate sorption sites in the soil, each with different reaction rates with each compound. A two-region advection-dispersion transport code was used to model the transport breakthrough curves. There was no evidence of transformation or degradation of the compounds during our sorption and transport studies.

  4. Geochemical characteristics of pyrite in Duolanasayi gold deposit, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    CHEN Guodong; XIAO Huiliang; WANG Henian; ZHOU Jiyuan


    The Duolanasayi gold deposit, 60 km NW of Habahe County, Xinjiang Uygur Autonomous Region, is a mid-large-scale gold deposit controlled by brittle-ductile shearing, and superimposed by albitite veins and late-stage magma hydrothermal solutions. There are four types of pyrite, which are contained in the light metamorphosed rocks (limestone, siltstone), altered-mineralized rocks (chlorite-schist, altered albite-granite, mineralized phyllite), quartz veins and carbonatite veinlets. The pyrite is the most common ore mineral. The Au-barren pyrite is present mainly in a simple form and gold-bearing pyrite is present mainly in a composite form. From the top downwards, the pyrite varies in crystal form from {100} and {210}+{100} to {210}+{100}+{111} to {100}+{111}. Geochemical studies indicate that the molecular contents of pyrite range from Fe1.057S2 to Fe0.941S2. Gold positively correlates with Mn, Sr, Zn, Te, Pb, Ba and Ag. There are four groups of trace elements: Fe-Cu-Sr-Ag, Au-Te-Co, As-Pb-Zn and Mn-V-Ti-Ba-Ni-Cr in pyrite. The REE characteristics show that the total amount of REE (ΣREE) ranges from 32.35×10 -6 to 132.18×10 -6; LREE/HREE, 4.466-9.142; (La/Yb)N, 3.719-11.133; (Eu/Sm)N, 0.553-1.656; (Sm/Nd)N, 0.602-0.717; La/Yb, 6.26-18.75; δEu, 0.628-2.309; δCe, 0.308-0.816. Sulfur isotopic compositions (δ 34S=-2.46‰--7.02‰) suggest that the sulfur associated with gold mineralization was derived from the upper mantle or lower crust.

  5. Interaction between river water and groundwater: Geochemical and anthropogenic influence (United States)

    Elango, L.; Karthikeyan, B.


    River water generally controls the quality and quantity of groundwater in its vicinity. Contribution by the rivers to groundwater is significant if there is over extraction. This is common in large cities where dependence on groundwater is high due to limited piped water supply. Chennai, India is one such large city where the river flowing is contaminated and the people in the near locality depend on groundwater for domestic use (Figure). The objective of this study is to understand the linkage between the river water and groundwater, and to assess the role played by the geochemical processes and anthropogenic influence. This study was carried out in and around Adyar River basin, Chennai by the collection of surface water and groundwater samples. Rainfall, lake water level and groundwater level from January 2005 to December 2009 was compared to understand their relationship. The concentration of major ion concentration vary widely in groundwater and surface water with respect to space and time. Na-Cl and Ca-Mg-Cl were the dominant groundwater and surface water type. Seawater intrusion may also be one of the reasons for Na-Cl dominant nature. In general, the ionic concentration of surface water increases towards the eastern part as in the case of groundwater. Evaporation and ion exchange were the major processes controlling groundwater chemistry in this area. Groundwater chemistry is similar to that of surface water. The surface water is contaminated due to discharge of industrial effluents and domestic sewage into the Adyar River by partly or untreated domestic sewage. Ecological restoration of Adyar River is planned and to be implemented shortly by the Government agencies which is expected to improve the river water quality. Systematic monitoring of water quality in this area will help to assess the improvement in surface water quality during the restoration process as well as its impact on groundwater.

  6. A Mobile App for Geochemical Field Data Acquisition (United States)

    Klump, J. F.; Reid, N.; Ballsun-Stanton, B.; White, A.; Sobotkova, A.


    We have developed a geochemical sampling application for use on Android tablets. This app was developed together with the Federated Archaeological Information Management Systems (FAIMS) at Macquarie University and is based on the open source FAIMS mobile platform, which was originally designed for archaeological field data collection. The FAIMS mobile platform has proved valuable for hydrogeochemical, biogeochemical, soil and rock sample collection due to the ability to customise data collection methodologies for any field research. The module we commissioned allows for using inbuilt or external GPS to locate sample points, it incorporates standard and incremental sampling names which can be easily fed into the International Geo-Sample Number (IGSN). Sampling can be documented not only in metadata, but also accompanied by photographic documentation and sketches. The module is augmented by dropdown menus for fields specific for each sample type and user defined tags. The module also provides users with an overview of all records from a field campaign in a records viewer. We also use basic mapping functionality, showing the current location, sampled points overlaid on preloaded rasters, and allows for drawing of points and simple polygons to be later exported as shape files. A particular challenge is the remoteness of the sampling locations, hundreds of kilometres away from network access. The first trial raised the issue of backup without access to the internet, so in collaboration with the FAIMS team and Solutions First, we commissioned a vehicle mounted portable server. This server box is constantly syncing with the tablets in the field via Wi-Fi, it has an uninterruptible power supply that can run for up to 45 minutes when the vehicle is turned off, and a 1TB hard drive for storage of all data and photographs. The server can be logged into via any of the field tablets or laptop to download all the data collected to date or to just view it on the server.

  7. A geochemical model of the Platanares geothermal system, Honduras (United States)

    Janik, C.J.; Truesdell, A.H.; Goff, F.; Shevenell, L.; Stallard, M.L.; Trujillo, P.E.; Counce, D.


    Results of exploration drilling combined with results of geologic, geophysical, and hydrogeochemical investigations have been used to construct a geochemical model of the Platanares geothermal system, Honduras. Three coreholes were drilled, two of which produced fluids from fractured Miocene andesite and altered Cretaceous to Eocene conglomerate at 450 to 680 m depth. Large volume artesian flows of 160-165??C, predominantly bicarbonate water are chemically similar to, but slightly less saline than widespread boiling hot-spring waters. The chemistry of the produced fluid is dominated by equilibrium reactions in sedimentary rocks at greater depths and higher temperatures than those measured in the wells. Chemical, isotope, and gas geothermometers indicate a deep fluid temperature of 200-245??C and reflect a relatively short residence time in the fractures feeding the wells. Chloride-enthalpy relations as well as isotopic and chemical compositions of well discharges, thermal springs, and local cold waters support a conceptual model of ascending high-temperature (minimum 225??C) parent fluid that has cooled conductively to form the 160-165??C shallow (to 680 m) fluid encountered by the wells. The hot-spring waters are formed by boiling and steam loss from more or less conductively cooled parent fluid. The more dilute boiling spring waters (Cl = ???32 mg/kg) have cooled from > 225??C to about 160??C by conduction and from 160??C to 98??C by boiling. The most concentrated boiling spring waters (Cl = 37 mg/kg) have cooled from > 225??C to about 200??C by conduction and from 200??C to 98??C by boiling. Intermediate concentrations reflect mixed cooling paths. ?? 1991.

  8. Geochemical characteristics and origin of light hydrocarbons in biogenic gas

    Institute of Scientific and Technical Information of China (English)


    The light hydrocarbon geochemical characteristics of biogenic gases from Sebei 1 gas field in the Qaidam Basin, Baoshan gas field in the Baoshan Basin and Alaxin gas field, Puqian gas pool, Aonan gas pool in the Songliao Basin are studied and the origin is discussed based on the composition and isotope data of gases. The isoalkane contents among light hydrocarbons in natural gas show a negative relationship with δ13C1 values. The isoalkane contents of the gases with δ13C1 values of less than ?60‰ are also high with more than 40% among light hydrocarbons in Sebei 1 gas field and Puqian gas pool. Moreover, the 2,2-dimethylbutane and 2-methylpentane, mainly sourced from bacteria, have predominance among isoalkanes, which suggests that light hydrocarbons in biogenic gases from these gas fields or pools were probably generated by microbial action. However, the cycloalkane contents among light hydrocarbons in biogenic gas are related to δ13C1 values positively. In Alaxin gas field and Aonan gas pool, where δ13C1 values of biogenic gases are less than ?60‰, the average contents of cycloalkane are higher than 44%. Light hydrocarbons among biogenic gases from these gas fields were probably generated by catalysis. The isoalkane and cycloalkane contents among light hydrocarbons from biogenic gases in the Baoshan gas field are both high, which might be generated by these two actions. The results show that the data of light hydrocarbons in biogenic gas can provide important information for understanding the generation mechanisms of light hydrocarbons during geological evolution and identifying biogenic gas and low mature gas.

  9. Enzymology of Electron Transport: Energy Generation with Geochemical Consequences

    Energy Technology Data Exchange (ETDEWEB)

    Dichristina, Thomas J.; Fredrickson, Jim K.; Zachara, John M.


    Dissimilatory metal-reducing bacteria (DMRB) are important components of the microbial community residing in redox-stratified freshwater and marine environments. DMRB occupy a central position in the biogeochemical cycles of metals, metalloids and radionuclides, and serve as catalysts for a variety of other environmentally important processes including biomineralization, biocorrosion, bioremediation and mediators of ground water quality. DMRB are presented, however, with a unique physiological challenge: they are required to respire anaerobically on terminal electron acceptors which are either highly insoluble (e.g., Fe(III)- and Mn(IV)-oxides) and reduced to soluble end-products or highly soluble (e.g., U(VI) and Tc(VII)) and reduced to insoluble end-products. To overcome physiological problems associated with metal and radionuclide solubility, DMRB are postulated to employ a variety of novel respiratory strategies not found in other gram-negative bacteria which respire on soluble electron acceptors such as O2, NO3- and SO42-. The novel respiratory strategies include (1) direct enzymatic reduction at the outer membrane, (2) electron shuttling pathways and (3) metal solubilization by exogenous or bacterially-produced organic ligands followed by reduction of soluble organic-metal compounds. The first section of this chapter highlights the latest findings on the enzymatic mechanisms of metal and radionuclide reduction by two of the most extensively studied DMRB (Geobacter and Shewanella), with particular emphasis on electron transport chain enzymology. The second section emphasizes the geochemical consequences of DMRB activity, including the direct and indirect effects on metal solubility, the reductive transformation of Fe- and Mn-containing minerals, and the biogeochemical cycling of metals at redox interfaces in chemically stratified environments.

  10. The geochemical transformation of soils by agriculture and its dependence on soil erosion: An application of the geochemical mass balance approach. (United States)

    Yoo, Kyungsoo; Fisher, Beth; Ji, Junling; Aufdenkampe, Anthony; Klaminder, Jonatan


    Agricultural activities alter elemental budgets of soils and thus their long-term geochemical development and suitability for food production. This study examined the utility of a geochemical mass balance approach that has been frequently used for understanding geochemical aspect of soil formation, but has not previously been applied to agricultural settings. Protected forest served as a reference to quantify the cumulative fluxes of Ca, P, K, and Pb at a nearby tilled crop land. This comparison was made at two sites with contrasting erosional environments: relatively flat Coastal Plain in Delaware vs. hilly Piedmont in Pennsylvania. Mass balance calculations suggested that liming not only replenished the Ca lost prior to agricultural practice but also added substantial surplus at both sites. At the relatively slowly eroding Coastal Plain site, the agricultural soil exhibited enrichment of P and less depletion of K, while both elements were depleted in the forest soil. At the rapidly eroding Piedmont site, erosion inhibited P enrichment. In similar, agricultural Pb contamination appeared to have resulted in Pb enrichment in the relatively slowly eroding Coastal Plain agricultural soil, while not in the rapidly eroding Piedmont soils. We conclude that agricultural practices transform soils into a new geochemical state where current levels of Ca, P, and Pb exceed those provided by the local soil minerals, but such impacts are significantly offset by soil erosion.

  11. Surveying Humaness

    DEFF Research Database (Denmark)

    Markussen, Randi; Gad, Christopher

    Christopher Gad. Ph.d. Dept. of Information and Media Studies Randi Markussen. Associate Professor, Dept. of Information and Media Studies.   Abstract:   Surveying humanness -politics of care improvement   For various reasons we both were subjected to a specific survey procedure...... and development of a large collection of biological and psychological symptoms and psycho-social problems. However, the surveys say nothing about how the information will be of use to the people who answer the procedure or how this scientific intervention will be put to use more specifically within the public...... carried out in a Danish county in order to improve treatment of people who have suffered from long-term illnesses. The surveys concern not only feed back on how people experience their present and past interaction with the social services and health care system; they also ask people to indicate the state...

  12. Surveying Humaness

    DEFF Research Database (Denmark)

    Markussen, Randi; Gad, Christopher

    Christopher Gad. Ph.d. Dept. of Information and Media Studies Randi Markussen. Associate Professor, Dept. of Information and Media Studies.   Abstract:   Surveying humanness -politics of care improvement   For various reasons we both were subjected to a specific survey procedure...... and development of a large collection of biological and psychological symptoms and psycho-social problems. However, the surveys say nothing about how the information will be of use to the people who answer the procedure or how this scientific intervention will be put to use more specifically within the public...... be imagined as a positive end, as ‘making explicit’ (in a popular psychological perspective) is considered to be therapeutic and good in itself? We will discuss those questions from a Foucaultian and ANT perspective, where one does not accept that pre-existing subjects are exposed to survey procedures...

  13. Survey Data (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Cleaned and QCd data for the Fishing Effort Survey. Questions on fishing and other out are asked on weather and outdoor activity, including fishing trips. Used for...

  14. Geochemical Data Package for Performance Assessment Calculations Related to the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, Daniel I. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    The Savannah River Site (SRS) disposes of low-level radioactive waste (LLW) and stabilizes high-level radioactive waste (HLW) tanks in the subsurface environment. Calculations used to establish the radiological limits of these facilities are referred to as Performance Assessments (PA), Special Analyses (SA), and Composite Analyses (CA). The objective of this document is to revise existing geochemical input values used for these calculations. This work builds on earlier compilations of geochemical data (2007, 2010), referred to a geochemical data packages. This work is being conducted as part of the on-going maintenance program of the SRS PA programs that periodically updates calculations and data packages when new information becomes available. Because application of values without full understanding of their original purpose may lead to misuse, this document also provides the geochemical conceptual model, the approach used for selecting the values, the justification for selecting data, and the assumptions made to assure that the conceptual and numerical geochemical models are reasonably conservative (i.e., bias the recommended input values to reflect conditions that will tend to predict the maximum risk to the hypothetical recipient). This document provides 1088 input parameters for geochemical parameters describing transport processes for 64 elements (>740 radioisotopes) potentially occurring within eight subsurface disposal or tank closure areas: Slit Trenches (ST), Engineered Trenches (ET), Low Activity Waste Vault (LAWV), Intermediate Level (ILV) Vaults, Naval Reactor Component Disposal Areas (NRCDA), Components-in-Grout (CIG) Trenches, Saltstone Facility, and Closed Liquid Waste Tanks. The geochemical parameters described here are the distribution coefficient, Kd value, apparent solubility concentration, ks value, and the cementitious leachate impact factor.

  15. Geochemical impacts of groundwater heat pump systems in an urban alluvial aquifer with evaporitic bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Garrido Schneider, Eduardo A. [Geological Survey of Spain (IGME), C/ Manuel Lasala no. 44, 9B, 50006 Zaragoza (Spain); García-Gil, Alejandro, E-mail: [Department of Earth Sciences, University of Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza (Spain); GHS, Institute of Environmental Assessment & Water Research (IDAEA), CSIC, Jordi Girona 18–26, 08034 Barcelona (Spain); Vázquez-Suñè, Enric [GHS, Institute of Environmental Assessment & Water Research (IDAEA), CSIC, Jordi Girona 18–26, 08034 Barcelona (Spain); Sánchez-Navarro, José Á. [Department of Earth Sciences, University of Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza (Spain)


    In the last decade, there has been an extensive use of shallow geothermal exploitations in urban environments. Although the thermal interference between exploitations has been recently studied, there is a lack of knowledge regarding the geochemical impacts of those systems on the aquifers where they are installed. Groundwater flow line scale and well-doublet scale research work has been conducted at city scale to quantify the geochemical interaction of shallow geothermal exploitations with the environment. A comprehensive analysis was conducted on data obtained from a monitoring network specifically designed to control and develop aquifer policies related to thermal management of the aquifer. The geochemical impacts were evaluated from a thermodynamic point of view by means of saturation index (SI) calculations with respect to the different mineral species considered in the system. The results obtained indicate limited geochemical interaction with the urban environment in most of the situations. However, there are some cases where the interaction of the groundwater heat pump installations with the evaporitic bedrock resulted in the total disablement of the exploitation system operation wells. The application of the tool proposed proved to be pragmatic in the evaluation of geochemical impacts. Injection of water into the aquifer can trigger an important bedrock gypsum and halite dissolution process that is partly responsible for scaling in well casing pipes and collapse of the terrain in the vicinity of injection wells. - Highlights: • We studied geochemical impacts of groundwater heat pump systems. • We have sampled a monitoring network in an energetically exploited urban aquifer. • A limited geochemical interaction has been found in most of the exploitations. • Reinjection into the aquifer produces an important bedrock gypsum dissolution. • Scaling in well casing pipes and collapse of the terrain have been observed.

  16. Geochemical Data Package for Performance Assessment Calculations Related to the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, Daniel I. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    The Savannah River Site (SRS) disposes of low-level radioactive waste (LLW) and stabilizes high-level radioactive waste (HLW) tanks in the subsurface environment. Calculations used to establish the radiological limits of these facilities are referred to as Performance Assessments (PA), Special Analyses (SA), and Composite Analyses (CA). The objective of this document is to revise existing geochemical input values used for these calculations. This work builds on earlier compilations of geochemical data, referred to a geochemical data packages (Kaplan, 2007; Kaplan, 2010; McDowell-Boyer et al., 2000). This work is being conducted as part of the on-going maintenance program of the SRS PA programs that periodically updates calculations and data packages when new information becomes available. Because application of values without full understanding of their original purpose may lead to misuse, this document also provides the geochemical conceptual model, the approach used for selecting the values, the justification for selecting data, and the assumptions made to assure that the conceptual and numerical geochemical models are reasonably conservative (i.e., bias the recommended input values to reflect conditions that will tend to predict the maximum risk to the hypothetical recipient). This document provides 1088 input parameters for geochemical parameters describing transport processes for 64 elements (>740 radioisotopes) potentially occurring within eight subsurface disposal or tank closure areas: Slit Trenches (ST), Engineered Trenches (ET), Low Activity Waste Vault (LAWV), Intermediate Level (ILV) Vaults, Naval Reactor Component Disposal Areas (NRCDA), Components-in-Grout (CIG) Trenches, Saltstone Facility, and Closed Liquid Waste Tanks. The geochemical parameters described here are the distribution coefficient, Kd value, apparent solubility concentration, ks value, and the cementitious leachate impact factor.

  17. Geochemical control processes and potential sediment toxicity in a mine-impacted lake. (United States)

    Adeleke, Solomon Babatunde; Svensson, Bo H; Yekta, Sepehr Shakeri; Adeleye, Michael Mayowa


    Geochemical parameters and major ion concentrations from sediments of a freshwater lake in the town of Åtvidaberg, southeastern, Sweden, were used to identify the geochemical processes that control the water chemistry. The lake sediments are anoxic, characterized by reduced sulfur and sulfidic minerals. The hypothesis tested is that in sulfidic-anaerobic contaminated sediments, the presence of redox potential changes creates a favorable condition for sulfide oxidation, resulting in the release of potentially toxic metals. The acid volatile sulfide (AVS) contents ranged from 5.5 μmol/g to 16 μmol/g of dry sediment. Comparison of total mine tailing metals (∑mine tailing metals) with simultaneously extracted metals (SEM) in sediments indicates that up to 20% of the ∑mine tailing metals are bound to the solid phase as AVS. Consequently, the AVS and SEM analysis classified all sediment samples as potentially toxic in terms of heavy metal concentrations (i.e., SEM to AVS ratio distribution > 1). Evaluation of hydrogeochemical data suggests that calcite dissolution, iron (III) oxyhydroxysulfate mineral jarosite (H-jarosite) precipitation, hematite precipitation, and siderite precipitation are the most prevailing geochemical processes that control the geochemical interactions between the water column and sediment in a mine-impacted lake. The geochemical processes were verified and quantified using a chemical equilibrium modeling program, Visual MINTEQ, Ver 3.1, beta. The identified geochemical processes create an environment in which the characteristics of sulfate-rich waters and acidic-iron produce the geochemical conditions for acid mine drainage and mobilization of toxic metals.

  18. Geochemical atlas of Radoviš and the environs and the distribution of heavy metals in the air


    Stafilov, Trajče; Balabanova, Biljana; Sajn, Robert; Baceva, Katerina; Boev, Blazo


    Introduction; Geographic description; Geological description; Material and methods: Sampling, Global positioning system, Sample preparation, Instrumentation, Reliability of chemical analysis; Data processing and drawing maps: Statistical analysis, Data mapping; Bio-monitoring with moss samples: Anthropogenic distribution of chemical elements; Geochemical association Al-As-Cd-Cu-Fe-Pb-Zn; Natural distribution of elements: Geochemical association Cr-Ni-Sr; Geochemical association Ba-K-Na; Monit...

  19. 中国多目标区域地球化学调查数据库建设及应用展望%China National Multi-purpose Geochemical Database Development and Application Prospect

    Institute of Scientific and Technical Information of China (English)

    刘荣梅; 吴轩; 向运川; 耿燕婷


    近10年我国多目标区域地球化学调查取得的系列成果是我国基础地学数据库系列中重要的地球化学数据资源.以全国30个省(区、市)1:25万多目标区域地球化学调查所获取数据,按照统一建库标准,首次汇总建成的全国多目标区域地球化学调查数据库,准确、全面地反映了我国生态环境信息,在地球化学编图、元素分布特征研究、地质环境研究、土地利用规划、农业结构调整、政府宏观决策等领域具有广阔的应用前景.系统地总结了全国多目标区域地球化学调查数据库结构与内容、建设方法、质量控制措施、全国多目标区域地球化学信息系统的主要功能及数据库成果的应用前景.%Approximately over the past 10 years, China multi-purpose geochemical survey have gained vast amounts of digital resources generated on over millions samples of surfacial material such as soils, stream sediments , waters, and rocks sampled by 30 provincial geological surveys and agencies. The national multi-purpose geochemical database representing these analyses contains in excess of 2. 2 millions pieces of record using a consistent set of methods. These data will compose a complete, national-scale multi-purpose geochemical coverage of China, and will enable construction of geochemical maps, refine estimates of baseline concentrations of chemical elements in the sampled media, and provide a wide prospects for variety of studies on the geological and environmental sciences, land and resource planning, agricultural restructuring and government's macro decision-making. This paper has summarized the structure and content, construction methods, quality-controlling measures, the prospects of applications of the national multi-objective geochemical database, including the main functions of the national multi-purpose geochemical information systems.

  20. Understanding sediment sources in a peri-urban Mediterranean catchment using geochemical tracers (United States)

    Ferreira, Carla; Walsh, Rory; Kikuchi, Ryunosuke; Blake, Will


    One of the main physical environmental impacts of urbanization is an increase in suspended sediment concentrations and loads, particularly in the constructional phase. Impacts in peri-urban catchments characterized by a mosaic of urban and non-urban landscape elements with varying roles in acting as sources and sinks of overland flow and slope wash have received little attention, particularly in Mediterranean environments. The present study uses a sediment 'fingerprinting' approach to determine the main sediment sources in the peri-urban Ribeira dos Covões catchment (6.2km2) in Portugal and how they change during storm events following contrasting antecedent weather. The catchment, rural until 1972, underwent discontinuous urbanization in 1973-1993, followed by an urban consolidation phase. Currently, its land-use is a complex mosaic of woodland (56%), urban (40%) and agricultural (4%) land parcels. Distinct urban patterns include some well-defined urban residential centres, but also areas of discontinuous urban sprawl. Since 2010, a major road was built and an enterprise park has been under construction, covering 1% and 5% of the catchment, respectively. The catchment has a Mediterranean climate. The geology comprises sandstone (56%), limestone (41%) and alluvial deposits (3%). Soils are generally deep (>3.0m), but shallow (transported fluvial material. Three fine bed-sediment sampling surveys were carried out after (i) a long dry period (21/09/2012), (ii) a winter storm of relatively high rainfall intensity (23.2mm day-1) (19/02/2015), and (iii) after several storms in Spring (22/04/2015). All samples were oven-dried (at 38° C) and sieved to obtain different particle size fractions (0.125-2.000mm, 0.063-0.125mm and road surface immediately it entered the stream network. The elemental composition (40 elements) of each size fraction was assessed using a Niton X-ray fluorescence elemental analyser. Results show that rock type has a profound influence on the

  1. Geochemical Characterization Using Geophysical Data and Markov Chain Monte Carlo Methods (United States)

    Chen, J.; Hubbard, S.; Rubin, Y.; Murray, C.; Roden, E.; Majer, E.


    Although the spatial distribution of geochemical parameters is extremely important for many subsurface remediation approaches, traditional characterization of those parameters is invasive and laborious, and thus is rarely performed sufficiently to describe natural hydrogeological variability at the field-scale. This study is an effort to jointly use multiple sources of information, including noninvasive geophysical data, for geochemical characterization of the saturated and anaerobic portion of the DOE South Oyster Bacterial Transport Site in Virginia. Our data set includes hydrogeological and geochemical measurements from five boreholes and ground-penetrating radar (GPR) and seismic tomographic data along two profiles that traverse the boreholes. The primary geochemical parameters are the concentrations of extractable ferrous iron Fe(II) and ferric iron Fe(III). Since iron-reducing bacteria can reduce Fe(III) to Fe(II) under certain conditions, information about the spatial distributions of Fe(II) and Fe(III) may indicate both where microbial iron reduction has occurred and in which zone it is likely to occur in the future. In addition, as geochemical heterogeneity influences bacterial transport and activity, estimates of the geochemical parameters provide important input to numerical flow and contaminant transport models geared toward bioremediation. Motivated by our previous research, which demonstrated that crosshole geophysical data could be very useful for estimating hydrogeological parameters, we hypothesize in this study that geochemical and geophysical parameters may be linked through their mutual dependence on hydrogeological parameters such as lithofacies. We attempt to estimate geochemical parameters using both hydrogeological and geophysical measurements in a Bayesian framework. Within the two-dimensional study domain (12m x 6m vertical cross section divided into 0.25m x 0.25m pixels), geochemical and hydrogeological parameters were considered as data

  2. Linking the climatic and geochemical controls on global soil carbon cycling (United States)

    Doetterl, Sebastian; Stevens, Antoine; Six, Johan; Merckx, Roel; Van Oost, Kristof; Casanova Pinto, Manuel; Casanova-Katny, Angélica; Muñoz, Cristina; Boudin, Mathieu; Zagal Venegas, Erick; Boeckx, Pascal


    Climatic and geochemical parameters are regarded as the primary controls for soil organic carbon (SOC) storage and turnover. However, due to the difference in scale between climate and geochemical-related soil research, the interaction of these key factors for SOC dynamics have rarely been assessed. Across a large geochemical and climatic transect in similar biomes in Chile and the Antarctic Peninsula we show how abiotic geochemical soil features describing soil mineralogy and weathering pose a direct control on SOC stocks, concentration and turnover and are central to explaining soil C dynamics at larger scales. Precipitation and temperature had an only indirect control by regulating geochemistry. Soils with high SOC content have low specific potential CO2 respiration rates, but a large fraction of SOC that is stabilized via organo-mineral interactions. The opposite was observed for soils with low SOC content. The observed differences for topsoil SOC stocks along this transect of similar biomes but differing geo-climatic site conditions are of the same magnitude as differences observed for topsoil SOC stocks across all major global biomes. Using precipitation and a set of abiotic geochemical parameters describing soil mineralogy and weathering status led to predictions of high accuracy (R2 0.53-0.94) for different C response variables. Partial correlation analyses revealed that the strength of the correlation between climatic predictors and SOC response variables decreased by 51 - 83% when controlling for geochemical predictors. In contrast, controlling for climatic variables did not result in a strong decrease in the strength of the correlations of between most geochemical variables and SOC response variables. In summary, geochemical parameters describing soil mineralogy and weathering were found to be essential for accurate predictions of SOC stocks and potential CO2 respiration, while climatic factors were of minor importance as a direct control, but are

  3. Geochemical exploration of the Chipilapa geothermal field, El Salvador

    Energy Technology Data Exchange (ETDEWEB)

    Nieva, David; Verma, Mahendra Pal; Santoyo, Edgar; Portugal, Enrique [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Campos, Alejandro [Comision Ejecutiva Hidroelectrica del Rio Lempa, Santa Tecla (El Salvador)


    Results of the geochemical exploration of the Ahuachapan-Chipilapa areas are presented. The procedure for interpreting the chemical composition of very dilute thermal waters is emphasised. Three groups of thermal waters are described, two with a geothermal brine component and one resulting from steam condensation. The model for one of the groups (Type 2) leads to predictions of temperature and chloride concentration that are reasonably close to those of the geothermal liquid feeding Chipilapa well CH-7B. In particular, it was predicted correctly that the salinities in the Chipilapa areas would be considerably lower than those in the Ahuachapan field. It is shown that the simultaneous modeling of the carbon dioxide concentration and isotopic composition of fumarole steam allows discrimination between primary and secondary steam. The composition of all fumarole samples is described as steam originating from a single reservoir fluid at 250degC, and composition {delta}{sup 18}O= - 4.1, {delta}D=-46, CO{sub 2}=5 x 10{sup -5} molar fraction. The total discharge composition of CH-7B confirms the trend observed in the Ahuachapan field of decreasing reservoir salinities towards the east. Postulating the existence of a deep reservoir brine in the eastern (Chipilapa) section of the system, with lower salinity but otherwise similar temperatures and isotopic composition to the Ahuachapan brine, allows for the generation of relatively simple models that explain the formation of the CH-7B brine, and the three groups of thermal waters. Type 1 waters are noteworthy in the sense that they result from a ternary mixture of meteoric water, geothermal brine and high-temperature steam condensate. The possibility that the east-west trend in salinity results from a process of dilution of brine with condensate from steam separated at very high temperatures is discussed. The distribution of the different types of hydrothermal manifestations delineates a lateral discharge system, with the

  4. An RET Experience with Geochemical Analysis of Azores Lavas (United States)

    Carpenter, C.; D'Albany, D.; Humayun, M.; Dixon, P.


    Each summer, the Center for Integrating Research and Learning (CIRL) at the National High Magnetic Field Laboratory (NHMFL) operates a Research Experiences for Teachers (RET) program. This six-week program provides stipends for teachers to work in the laboratories of NHMFL scientists. Faculty members of the Geochemistry Program at the NHMFL frequently host RET teachers to facilitate the broader dissemination of Geoscience knowledge among K-12 educators. During the summer of 2009, David d’Albany and Charles Carpenter, participated in the RET program for K-12 teachers at the NHMFL in Tallahassee, Florida. Mr. d’Albany is a Biology teacher at King IB High School in Tampa, Florida. Mr. Carpenter is a Physics teacher at Lawton Chiles High School in Tallahassee, Florida. Both teachers had the opportunity to analyze the elemental composition of a volcanic rock from the Azores Islands, in the North Atlantic. The Azores Islands represent a set of nine volcanic islands, near the active Azores Triple Junction, on the mid-Atlantic Ridge around 38°N, generally conceived as the products of a deep mantle plume. The analytical method used was Laser Ablation Inductively Coupled Plasma Mass Spectrometry (ICP-MS) using a New Wave UP193FX excimer laser ablation system coupled to a Thermo Element XR magnetic sector ICP-MS. This method allowed solid sampling of a large area of the basaltic matrix, and separately of the olivine (peridot) crystals within the matrix, from a lava sample from the island of Faial. Elemental data were obtained on a broader spectrum of elements (65 elements) than currently available in the geochemical literature for these islands. Chondrite-normalized rare earth element abundances for the sample provided a precise match with data for other lavas from the island of Faial from the GEOROC database. It should be noted that all 14 lanthanides, excluding Pm, were measured with ICP-MS, compared with about 8 elements determined by previous bulk rock techniques

  5. Western Alborz Volcanic Rocks, a new Geochemical Viewpoint (United States)

    Ghorbani, M.


    Volcanic and pyroclastic rocks of Eocene age comprise vast outcrops of Alborz Mountain Range, a fold-thrusted structural unit extending across northern Iran for 2000 km in a curvilinear pattern. In his account of structural evolution of Iranian plateau, Berberian (1983; p. 55) ascribed these rocks to a subduction-type magmatism. Based on a tectonostratigraphic study, these rocks are attributed to an arc-type magmatism (Alavi; 1996, p. 29). Recently a new data set of major and trace element (including REE) analyses of volcanic rocks from western Alborz, some 50 km west of city of Qazvin, has been made available (Asiabanha, 2001). Careful examination of the data (i.e., those of basic-intermediate rocks) in present study revealed, for the first time, some geochemical characteristics which have important implications on the geodynamic synthesis of this structural unit. The rocks contain 50-60 wt% SiO2. They lie in the midalkaline-to-subalkaline domain of TAS diagram (Middlemost, 1997; p.216) and fall in the calcalkaline field of AFM diagram. The volcanic rocks display two distinct chondrite-normalized REE patterns, one is MREE-depleted while the other is a rather smooth uniform M-HREE pattern. These are called MREE-depleted and smooth M-HREE series. Basic rocks from the latter contain higher silica than the former (>53 vs. >50 wt%), yet they show lower incompatible elements (e.g., K and Rb) and HFSE contents. These features can not be explained by differentiation and might be interpreted as implying the involvement of two source regions. Chondrite-normalized trace element patterns of the MREE-depleted series is more akin to the island arc calcalkaline (IACA) basic rocks than the basic rocks from any other tectonic settings. However, island arc products, known for being depleted in HFSE relative to other incompatible elements, differ from the MREE-depleted series which is rich in both HFSE and incompatible elements. One may advocate the role of OIB-type mantle

  6. The Geochemical Behavior and Transport Characteristics of Xenoestrogens (United States)

    Wallace, T. C.; Bennett, P. C.


    Xenoestrogens are estrogenic active synthetic chemicals that mimic the actions of female sex hormones. Xenoestrogens can be produced synthetically and naturally, and exposure can occur from a variety of sources- food additives, plastics, pesticides, or pharmaceuticals. These environmental chemicals are also known as endocrine disruptors because exposure to low doses (ng/L) have been linked to adverse effects in the reproductive and developmental stages in aquatic species (i.e. reproductive anomalies, feminization, infertility, alterations in growth during life cycles, and changes in community structures). Determining the exposure risks of these toxicological compounds, however, requires a better understanding of the geochemical behavior and transport of synthetic estrogens it is discharged to. Estrogen and its metabolites are also useful tracers because of their specific medical usage (sources from birth control pills, estrogen replacement therapy, and livestock farming), slow degradation before excretion, and unique physiochemical properties (low volatility, hydrophobicity, and high Kow). Estradiol concentrations analyzed by an enzyme-linked immunoassay (ELISA) show that <2-55 ng/L are discharged to Walnut Creek, a stream that also connects to the Colorado River(TX). The bioavailability of these compounds is affected by sorption processes, where xenoestrogens become associated with solid phases. A series of batch sorption experiments using sediment collected from Walnut Creek downstream of an Austin waste water treatment plant and synthetic estrogen standards (Simga@ Estrone, 17B-Estradiol, and Estriol), examined the distribution of estrogen between solid and aqueous phases. Analysis of the concentrations sorbed to sediment result in Freundlich sorption isotherms using HPLC/UV techniques (High Performance Liquid Chromatography with UV detectors- 220 and 280nm). Sorption occurs rapidly with 98% of 17B-Estradiol sorbed within 30 minutes (Estriol=80%, Estrone=95

  7. New Geochemical Data on Postcollisional Ultrapotassic Rocks in Western Tibet (United States)

    Zhao, Z.; Mo, X.; Depaolo, D.; Owens, T.; Liao, Z.; Zhu, D.


    We studied the postcollisional ultrapotassic volcanic rocks in Gongmutang (N30° 48', E84° 26'), Zabuye salt lake (N31° 26', E84° 20'), Dangreyong lake (N30° 57', E86° 24'), and Xuru lake (N30° 4', E86° 31') in western Lhasa block. These rocks erupted during the time between 27 Ma and 12 Ma ago according to published dating work. They are strongly related to the north-south trending normal faults or valley in tectonic setting. These lavas (SiO2=45-62%, K2O=6.0-8.8%, K2O/Na2O=2.0-4.3%, MgO=2.5-10.9%, TiO2=0.8-1.6%) are very homogenous in trace element composition, with enriched LREE, Rb, Ba, Th, and U, and depleted Nb, Ta, and Ti. These samples, with ɛ Nd varies from -11 to -15 and 87Sr/86Sr from 0.718 to 0.736, show much different isotopic features to the postcollisional shoshonitic-dominated rocks in North Tibet (ɛ Nd varies from -5 to -9 and 87Sr/86Sr from 0.708 to 0.711). But they shift much close or even overlap the Himalayan basement and granitoid Nd-Sr field (ɛ Nd range from -12 to -25 and 87Sr/86Sr from 0.733 to 0.760). The geochemical characteristics of the rocks in our study are similar to the rocks from Shiquanhe (Turner et al., 1996, J. Petrol.), Xunba (Miller et al., 1999, J Petrol), and Pabbai Zong (Williams et al., 2001, Geology). If we take the widely-accepted origin hypotheses that the ultrapotassic lavas is firstly derived from small degree partial melting of subcontinental lithospheric mantle, we could conclude that an enriched mantle source should be responsible for the lavas in western Tibet. The Nd-Sr isotopic data suggest that at least two possibilities for the structure and composition of the lithosphere in western Tibet: (1) The Himalayan basement affinity of these lavas suggest that the Himalayan crustal materials in the northern margin of Indian plate maybe a reagent that enriched the upper mantle of the western Lhasa block. If this is the fact, the northern part of India would have subducted beneath Lhasa block that suggested by

  8. Community-Based Development of Standards for Geochemical and Geochronological Data (United States)

    Lehnert, K. A.; Walker, D.; Vinay, S.; Djapic, B.; Ash, J.; Falk, B.


    The Geoinformatics for Geochemistry (GfG) Program ( and the EarthChem project ( aim to maximize the application of geochemical data in Geoscience research and education by building a new advanced data infrastructure for geochemistry that facilitates the compilation, communication, serving, and visualization of geochemical data and their integration with the broad Geoscience data set. Building this new data infrastructure poses substantial challenges that are primarily cultural in nature, and require broad community involvement in the development and implementation of standards for data reporting (e.g., metadata for analytical procedures, data quality, and analyzed samples), data publication, and data citation to achieve broad acceptance and use. Working closely with the science community, with professional societies, and with editors and publishers, recommendations for standards for the reporting of geochemical and geochronological data in publications and to data repositories have been established, which are now under consideration for adoption in journal and agency policies. The recommended standards are aligned with the GfG and EarthChem data models as well as the EarthChem XML schema for geochemical data. Through partnerships with other national and international data management efforts in geochemistry and in the broader marine and terrestrial geosciences, GfG and EarthChem seek to integrate their development of geochemical metadata standards, data format, and semantics with relevant existing and emerging standards and ensure compatibility and compliance.

  9. Helium and lead isotopes reveal the geochemical geometry of the Samoan plume. (United States)

    Jackson, M G; Hart, S R; Konter, J G; Kurz, M D; Blusztajn, J; Farley, K A


    Hotspot lavas erupted at ocean islands exhibit tremendous isotopic variability, indicating that there are numerous mantle components hosted in upwelling mantle plumes that generate volcanism at hotspots like Hawaii and Samoa. However, it is not known how the surface expression of the various geochemical components observed in hotspot volcanoes relates to their spatial distribution within the plume. Here we present a relationship between He and Pb isotopes in Samoan lavas that places severe constraints on the distribution of geochemical species within the plume. The Pb-isotopic compositions of the Samoan lavas reveal several distinct geochemical groups, each corresponding to a different geographic lineament of volcanoes. Each group has a signature associated with one of four mantle endmembers with low (3)He/(4)He: EMII (enriched mantle 2), EMI (enriched mantle 1), HIMU (high µ = (238)U/(204)Pb) and DM (depleted mantle). Critically, these four geochemical groups trend towards a common region of Pb-isotopic space with high (3)He/(4)He. This observation is consistent with several low-(3)He/(4)He components in the plume mixing with a common high-(3)He/(4)He component, but not mixing much with each other. The mixing relationships inferred from the new He and Pb isotopic data provide the clearest picture yet of the geochemical geometry of a mantle plume, and are best explained by a high-(3)He/(4)He plume matrix that hosts, and mixes with, several distinct low-(3)He/(4)He components.

  10. Geochemical impacts of groundwater heat pump systems in an urban alluvial aquifer with evaporitic bedrock. (United States)

    Garrido Schneider, Eduardo A; García-Gil, Alejandro; Vázquez-Suñè, Enric; Sánchez-Navarro, José Á


    In the last decade, there has been an extensive use of shallow geothermal exploitations in urban environments. Although the thermal interference between exploitations has been recently studied, there is a lack of knowledge regarding the geochemical impacts of those systems on the aquifers where they are installed. Groundwater flow line scale and well-doublet scale research work has been conducted at city scale to quantify the geochemical interaction of shallow geothermal exploitations with the environment. A comprehensive analysis was conducted on data obtained from a monitoring network specifically designed to control and develop aquifer policies related to thermal management of the aquifer. The geochemical impacts were evaluated from a thermodynamic point of view by means of saturation index (SI) calculations with respect to the different mineral species considered in the system. The results obtained indicate limited geochemical interaction with the urban environment in most of the situations. However, there are some cases where the interaction of the groundwater heat pump installations with the evaporitic bedrock resulted in the total disablement of the exploitation system operation wells. The application of the tool proposed proved to be pragmatic in the evaluation of geochemical impacts. Injection of water into the aquifer can trigger an important bedrock gypsum and halite dissolution process that is partly responsible for scaling in well casing pipes and collapse of the terrain in the vicinity of injection wells. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Geochemical investigation of iron transport into bentonite as steel corrodes

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, Fiona; Bate, Fiona; Heath, Tim; Hoch, Andrew [Serco Assurance, Harwe ll (United Kingdom)


    some experiments. Using the experimental data as a guide, a modelling investigation has been carried out. The objectives of the modelling investigation were: To develop a geochemical model of the transport of iron into bentonite based on the clear experimental evidence of the penetration of iron into bentonite. To improve our understanding of the desaturation of the bentonite as water is consumed during the corrosion process and the resultant gas(es) escapes. The production of iron from the corroding source was modelled using a rate of gas evolution that had been fitted. It was shown that ion exchange and surface complexation processes do not provide sufficient sorption to predict the high amount of iron observed in the solid phase. Therefore alternative processes, such as iron-containing mineral formation or mineral transformations, were also suggested to account for the amount of iron observed within the bentonite phase. Magnetite was identified as the most thermodynamically stable solubility limiting phase under the experimental conditions. A one-dimensional transport model was constructed to include all relevant processes. The simulations considered the diffusive transport of Fe{sup 2+} ions away from a corroding source, using the rate of gas evolution resulting from the corrosion process. Ion exchange and surface complexation processes were allowed within the bentonite which would provide sorption of iron onto and within the bentonite solid. The pH was buffered by allowing protonation and deprotonation of the surface sites of the bentonite solid. In addition, saturation of iron-containing minerals was permitted. The base case model suggests that about 4.4 wt % of iron could form in the bentonite if the formation of magnetite was allowed. However, the maximum theoretical amount of iron available from the source term is limited to 4.5 wt % of iron by the cumulative gas evolution rate, which is lower than the observed amount of iron in the bulk bentonite (6.6 wt

  12. Engineering surveying

    CERN Document Server

    Schofield, W


    Engineering surveying involves determining the position of natural and man-made features on or beneath the Earth's surface and utilizing these features in the planning, design and construction of works. It is a critical part of any engineering project. Without an accurate understanding of the size, shape and nature of the site the project risks expensive and time-consuming errors or even catastrophic failure.Engineering Surveying 6th edition covers all the basic principles and practice of this complex subject and the authors bring expertise and clarity. Previous editions of this classic text have given readers a clear understanding of fundamentals such as vertical control, distance, angles and position right through to the most modern technologies, and this fully updated edition continues that tradition.This sixth edition includes:* An introduction to geodesy to facilitate greater understanding of satellite systems* A fully updated chapter on GPS, GLONASS and GALILEO for satellite positioning in surveying* Al...


    Directory of Open Access Journals (Sweden)

    Alexei V. Ivanov


    Full Text Available Geochemical features for volcanic rocks and petrologic data for deep-seated inclusions, which can be used to infer mass transfer between different geospheres, are reviewed. It is typically believed that slabs can subduct as deep as the core-mantle boundary with the following recycling by plumes coming up to the sublithospheric regions of magma generation. However, the petrologic evidence of the deepest accessible material is limited by the depth of the uppermost lower mantle (~650–700km, i.e. by the depth of the deepest earthquakes. Ferropericlase inclusions in some diamonds do not exclude involvement of deeper mantle horizons, yet do not unambiguously support it. No unambiguous confirmation of involvement of the lower mantle into magma generation underneath volcanically active regions is obtained from geochemical data either, while the geochemical data suggest complete chemical isolation of the Earth’s core from the upper mantle processes.

  14. The Porretta thermal springs (Northern Apennines: seismogenic structures and long-term geochemical monitoring

    Directory of Open Access Journals (Sweden)

    F. Italiano


    Full Text Available The thermal springs of Porretta are located on a seismically active area of the Northern Apennines. In 19th Century a chemist identified anomalous behaviour of the thermal waters in concomitance with local seismic events. Recent studies assessed the geochemical features of the circulating fluids (e.g., waters carry a dissolved CH4-dominated gas phase with a radiogenic signature of the helium isotopic ratio and observed anomalous hydrologic and geochemical signals possibly related to crustal strain phenomena due to local seismic events. Long-term geochemical monitoring was carried out from 2001 to 2006 with the aim of detecting the behaviour of the circulating fluids possibly coinciding with seismic activity. The collected data reveal a sensitivity of the thermal waters to the activity of the main fault crossing the village of Porretta and identify a «seismogenic» structure crossing the village.

  15. Acceptance of the 2014 Geochemical Society Distinguished Service Award by Carla Koretsky (United States)

    Koretsky, Carla


    I am deeply touched to have received the Geochemical Society Distinguished Service Award. It was a great surprise when I received the notice that I had been chosen for the award. It has been a tremendous pleasure to work on behalf of student members of the Geochemical Society, Japanese Geochemical Society and the European Association of Geochemists to organize the student travel grants over the past few years. Certainly, this is not an effort that I undertook on my own. Many, many members of the GS, the JGS and the EAG generously donated their time and expertise to serve as reviewers for the many travel grant applicants we receive each year. Seth Davis, the GS Chief Operating Officer, spent countless hours helping to organize applications, the website, distribution of funds and many other aspects of the competition. Without Seth and the many expert reviewers, we could not run the travel grant program each year and provide this important financial support to allow more students to experience the Goldschmidt Conference. I also enjoyed my time as Geochemical News co-editor, and I should point out that GN during those years was ably co-edited by Johnson Haas. It has been a pleasure to see Elements take off, and GN evolve into a timely source of important announcements and information about cutting-edge science since I stepped down as co-editor. I feel very fortunate to work with so many outstanding colleagues in the global geochemical community, and I am a little embarrassed, and also very grateful, to have been selected for the Geochemical Society Distinguished Service Award. Thank you!

  16. Application of Fourier and wavelet approaches for identification of geochemical anomalies (United States)

    Shahi, Hossein; Ghavami, Reza; Kamkar Rouhani, Abolghasem; Roshandel Kahoo, Amin; Asadi Haroni, Hooshang


    The geochemical data can be transferred to other domains such as frequency and position-scale domains using Fourier transform (FT) and wavelet transform (WT). The investigations made in this paper show the analysis of geochemical data in frequency and position-scale domains can provide new exploratory information that may not be revealed in the spatial domain (SD). The geochemical data of Dalli porphyry deposit (Central Iran) have been examined in SD using principal component analysis (PCA), and as a result, Cu, Au and Mo have been identified as mineralization elements. In this study, to determine the mineralization pattern and identify the new exploration target in Dalli area, FT and WT have been performed on surface geochemical data and then, the obtained data have been analyzed using PCA separately. The results of this analysis on soil geochemical data in frequency domain (FD) have desirably identified the mineralization elements of Au, Cu, Mo and S. In next step, PCA has also been performed on approximate component in one level of position-scale domain, and then, a new index has been presented based on wavelet coefficients, and consequently, significant results have been obtained by PCA of the index. The results of this index have desirably identified the mineralization elements of Au, Cu and Mo unlike the approximate component. Finally, the elements of Au, Cu and Mo have been classified clearly using the combination of mineralization factors extracted from FT and WT. The geochemical distribution maps obtained from FD and SD have been depicted. Information obtained from the exploration drillings such as trenches and boreholes in the study area confirm the analysis results of FT and WT.

  17. Risk evaluation of uranium mining: A geochemical inverse modelling approach (United States)

    Rillard, J.; Zuddas, P.; Scislewski, A.


    It is well known that uranium extraction operations can increase risks linked to radiation exposure. The toxicity of uranium and associated heavy metals is the main environmental concern regarding exploitation and processing of U-ore. In areas where U mining is planned, a careful assessment of toxic and radioactive element concentrations is recommended before the start of mining activities. A background evaluation of harmful elements is important in order to prevent and/or quantify future water contamination resulting from possible migration of toxic metals coming from ore and waste water interaction. Controlled leaching experiments were carried out to investigate processes of ore and waste (leached ore) degradation, using samples from the uranium exploitation site located in Caetité-Bahia, Brazil. In experiments in which the reaction of waste with water was tested, we found that the water had low pH and high levels of sulphates and aluminium. On the other hand, in experiments in which ore was tested, the water had a chemical composition comparable to natural water found in the region of Caetité. On the basis of our experiments, we suggest that waste resulting from sulphuric acid treatment can induce acidification and salinization of surface and ground water. For this reason proper storage of waste is imperative. As a tool to evaluate the risks, a geochemical inverse modelling approach was developed to estimate the water-mineral interaction involving the presence of toxic elements. We used a method earlier described by Scislewski and Zuddas 2010 (Geochim. Cosmochim. Acta 74, 6996-7007) in which the reactive surface area of mineral dissolution can be estimated. We found that the reactive surface area of rock parent minerals is not constant during time but varies according to several orders of magnitude in only two months of interaction. We propose that parent mineral heterogeneity and particularly, neogenic phase formation may explain the observed variation of the

  18. A Geochemical Study of Russian Eucrites and Howardites (United States)

    Lindstrom, M. M.; Mittlefehldt, D. W.


    ; those of normal eucrites and HREE are below the detection limits. The Eu/Sm ratio is about twice that typical of cumulate eucrites, but both Fe and Ca concentrations are within the range of cumulate eucrites. The Yurtuk clast was received as debris. The presence of one ~4-mm plagioclase fragment suggests that the clast is relatively coarse-grained. The sample may not be representative of the original rock as we estimated that there was only ~20% pyroxene in the debris, much less than in cumulate eucrites. This is borne out by our analyses: Ca is atypically high and Fe and Sc are atypically low for cumulate eucrites. The REE pattern is flat at about 10% that of normal eucrites, except for a positive Eu anomaly, and appears to be that of a plagioclase-rich cumulate eucrite. Whole Rock Howardites. Whole rock samples of Erevan, Yurtuk, and Zmenj are typical howardites with compositions intermediate between eucrites and diogenites. Compared to typical eucrites, they have low Ca, Fe, and Sc, and high Cr. Based on Ca content, Erevan, Yurtuk, and Zmenj are estimated to contain approximately 67%, 55%, and 46% basaltic component, respectively. High concentrations of siderophile elements, Co (14-34 micrograms/g), Ni (30-200 micrograms/g) and Ir (up to 3 ng/g), are evidence for a chondritic component of up to 2% in the breccias. This geochemical study of six Russian eucrites and howardites has shown that most are fairly typical HED meteorites, but has identified two cumulate eucrite clasts and shown that Vetluga may be intermediate in composition between typical and evolved eucrites.

  19. Organic geochemical study of domanik deposits, Tatarstan Republic. (United States)

    Nosova, F. F.; Pronin, N. V.


    High-bituminous argillo-siliceous carbonate deposits of domanik formation (DF) occurring within pale depressions and down warps in the east of the Russian platform are treated by many investigators as a main source of oil and gas in the Volga-Ural province. In this study a special attention was turned to organic-rich rocks DF witch outcrop in the central part (Uratminskaya area 792, 806 boreholes) and in the west part (Sviyagskaya, 423) of the Tatarstan Republic. The aim of the present paper is to characterize the organic matter: origin, depositional environments, thermal maturity and biodegradation-weathering effects. Nowadays the most informative geochemical parameters are some biomarkers which qualitatively and are quantitatively defined from distributions of n-alkanes and branched alkanes. Biomarkers - it's original fingerprints of biomass of organic matter, that reflect molecular hydrocarbonic structure. The bulk, molecular composition of oil is initially a function of the type and maturity of the source rock from which it has been expelled, while the source rock type reflects both the nature of precursor organisms and the conditions of its deposition. Methodology used in this study included sampling, bitumen extraction, liquid-column chromatography and gas chromatography/mass spectrometry analyses. The bitumen was fractionated by column chromatography on silica gel. Non-aromatic or alifatics, aromatics and polar compounds were obtained. Alifatic were analysed by gas chromatography/mass spectrometry Percin Elmer. The hydrocarbons present in the sediments of DF and have a carbon numbers ranging from 12 through 38. The samples contain variably inputs from both terrigenous and non-terrigenous (probably marine algal) organic matter as evident in bimodal GC fingerprints of some samples. Pristane and phytane, also, occur in very high concentration in sample extracts. The relatively low Pr/Ph ratios, CPI and OEPbiomarkers distribution of the domanic samples generally

  20. Near-surface electromagnetic, rock magnetic, and geochemical fingerprinting of submarine freshwater seepage at Eckernförde Bay (SW Baltic Sea) (United States)

    Müller, Hendrik; von Dobeneck, Tilo; Nehmiz, Wiebke; Hamer, Kay


    Submarine groundwater discharge in coastal settings can massively modify the hydraulic and geochemical conditions of the seafloor. Resulting local anomalies in the morphology and physical properties of surface sediments are usually explored with seismo-acoustic imaging techniques. Controlled source electromagnetic imaging offers an innovative dual approach to seep characterization by its ability to detect pore-water electrical conductivity, hence salinity, as well as sediment magnetic susceptibility, hence preservation or diagenetic alteration of iron oxides. The newly developed electromagnetic (EM) profiler Neridis II successfully realized this concept for a first time with a high-resolution survey of freshwater seeps in Eckernförde Bay (SW Baltic Sea). We demonstrate that EM profiling, complemented and validated by acoustic as well as sample-based rock magnetic and geochemical methods, can create a crisp and revealing fingerprint image of freshwater seepage and related reductive alteration of near-surface sediments. Our findings imply that (1) freshwater penetrates the pore space of Holocene mud sediments by both diffuse and focused advection, (2) pockmarks are marked by focused freshwater seepage, underlying sand highs, reduced mud thickness, higher porosity, fining of grain size, and anoxic conditions, (3) depletion of Fe oxides, especially magnetite, is more pervasive within pockmarks due to higher concentrations of organic and sulfidic reaction partners, and (4) freshwater advection reduces sediment magnetic susceptibility by a combination of pore-water injection (dilution) and magnetite reduction (depletion). The conductivity vs. susceptibility biplot resolves subtle lateral litho- and hydrofacies variations.

  1. Some geochemical considerations for a potential repository site in tuff at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Erdal, B.R.; Bish, D.L.; Crowe, B.M.; Daniels, W.R.; Ogard, A.E.; Rundberg, R.S.; Vaniman, D.T.; Wolfsberg, K.


    The Nevada Nuclear Waste Storage Investigations, which is evaluating potential locations for a high-level waste repository at the Nevada Test Site and environs, is currently focusing its investigations on tuff, principally in Yucca Mountain, as a host rock. This paper discusses some of the geochemical investigations. Particular emphasis is placed on definition of some basic elements and necessary technical approaches for the geochemistry data acquisition and modeling program. Some site-specific tuff geochemical information that is important for site selection and repository performance will be identified and the current status of knowledge will then be discussed.

  2. Some isotopic and geochemical anomalies observed in Mexico prior to large scale earthquakes and volcanic eruptions

    Energy Technology Data Exchange (ETDEWEB)

    Cruz R, S. de la; Armienta, M.A.; Segovia A, N


    A brief account of some experiences obtained in Mexico, related with the identification of geochemical precursors of volcanic eruptions and isotopic precursors of earthquakes and volcanic activity is given. The cases of three recent events of volcanic activity and one large earthquake are discussed in the context of an active geological environment. The positive results in the identification of some geochemical precursors that helped to evaluate the eruptive potential during two volcanic crises (Tacana 1986 and Colima 1991), and the significant radon-in-soil anomalies observed during a volcanic catastrophic eruption (El Chichon, 1982) and prior to a major earthquake (Michoacan, 1985) are critically analysed. (Author)

  3. Soil-geochemical factors of rocket fuel migration in the landscape (United States)

    Krechetov, P. P.; Kasimov, N. S.; Koroleva, T. V.


    The effect of different soil-geochemical factors on the migration of asymmetric dimethylhydrazine (UDMH) in the landscape has been studied. Experimental studies have been performed on soil and rock samples with specified parameters of the material composition. The effect of organic matter, acid-base properties, particle size distribution, and mineralogy on the decrease in the concentration of UDMH in equilibrium solutions has been studied. It has been found that the soil-geochemical factors are arranged in the following series according to the effect on UDMH mobility: acid-base properties > organic matter content > clay fraction mineralogy > particle size distribution.

  4. Interaction of density flow and geochemical processes on islands in the Okavanga Delta, Botswana

    DEFF Research Database (Denmark)

    Bauer-Gottwein, Peter; Langer, T.; Prommer, H.


    This paper analyses the interactions of density driven flow and geochemical reactions under evapo-concentration. A multi-species hydrodynamic flow and transport simulation model (SEAWAT) is coupled to a batch reaction model (PHREEQC) to analyze densitydriven flow on islands in the Okavango Delta......, Botswana. Evapo-concentration on the islands leads to steadily increasing concentrations until the onset of density-driven flow against the evaporation-induced upward gradient. Lag times to the onset of density-driven flow are strongly influenced by geochemical reactions. Mineral precipitation and carbon...

  5. Happiness Survey

    Institute of Scientific and Technical Information of China (English)


    Are Chinese people happy in today’s fast-paced, modern society? What are the sources of their happiness? In today’s rapidly developing economy, is happiness closely related to wealth or not? A recent happiness survey conducted in China gives some answers.

  6. Aquifer Storage and Recovery : Physical and Geochemical Modelling (SWIFTPHREEQC)of British Aquifers for Aquifer Storage and Recovery Purposes. Part 1, physical modelling and geochemical model calibration



    This report describes the progress that has been made in developing models simulating both the physical and geochemical aspects of Aquifer Storage Recovery (ASR) schemes. This work is part of a 30 month project, entitled ASR-UK, which started in April 1999. The report describes progress to the end of 1999. SWIFT is a fully transient 3-Dimensional model that simulates flow and transport of fluids. It is ideally suited to modelling ASR and has been used to simulate the response o...

  7. Metagenomic and geochemical characterization of pockmarked sediments overlaying the Troll petroleum reservoir in the North Sea

    Directory of Open Access Journals (Sweden)

    Håvelsrud Othilde


    Full Text Available Abstract Background Pockmarks (depressions in the seabed have been discovered throughout the world’s oceans and are often related to hydrocarbon seepage. Although high concentrations of pockmarks are present in the seabed overlaying the Troll oil and gas reservoir in the northern North Sea, geological surveys have not detected hydrocarbon seepage in this area at the present time. In this study we have used metagenomics to characterize the prokaryotic communities inhabiting the surface sediments in the Troll area in relation to geochemical parameters, particularly related to hydrocarbon presence. We also investigated the possibility of increased potential for methane oxidation related to the pockmarks. Five metagenomes from pockmarks and plain seabed sediments were sequenced by pyrosequencing (Roche/454 technology. In addition, two metagenomes from seabed sediments geologically unlikely to be influenced by hydrocarbon seepage (the Oslofjord were included. The taxonomic distribution and metabolic potential of the metagenomes were analyzed by multivariate analysis and statistical comparisons to reveal variation within and between the two sampling areas. Results The main difference identified between the two sampling areas was an overabundance of predominantly autotrophic nitrifiers, especially Nitrosopumilus, and oligotrophic marine Gammaproteobacteria in the Troll metagenomes compared to the Oslofjord. Increased potential for degradation of hydrocarbons, especially aromatic hydrocarbons, was detected in two of the Troll samples: one pockmark sample and one from the plain seabed. Although presence of methanotrophic organisms was indicated in all samples, no overabundance in pockmark samples compared to the Oslofjord samples supports no, or only low level, methane seepage in the Troll pockmarks at the present time. Conclusions Given the relatively low content of total organic carbon and great depths of hydrocarbon containing sediments in the Troll

  8. Petrological and Geochemical characterization of central Chihuahua basalts: a possible local sign of rifting activity (United States)

    Espejel-Garcia, V. V.; Garcia-Rascon, M.; Villalobos-Aragon, A.; Morton-Bermea, O.


    The central part of the mexican state, Chihuahua, is the oriental border of the Sierra Madre Occidental (silicic large igneous province), which consist of series of ignimbrites divided into two volcanic groups of andesites and rhyolites. In the central region of Chihuahua, the volcanic rocks are now part of the Basin and Range, allowing the presence of mafic rocks in the lower areas. The study area is located approximately 200 km to the NW of Chihuahua city near to La Guajolota town, in the Namiquipa County. There are at least 5 outcrops of basalts to the west of the road, named Puerto de Lopez, Malpaises, El Tascate, Quebrada Honda, and Carrizalio, respectively. These outcrops have only been previously described by the Mexican Geologic Survey (SGM) as thin basaltic flows, with vesicles filled with quartz, and phenocrystals of labradorite, andesine, oligoclase and olivine. Petrologically, the basalts present different textures, from small phenocrysts of plagioclase in a very fine matrix to large, zoned and sometimes broken phenocrysts of plagioclase in a coarser matrix. All samples have olivine in an advanced state of alteration, iddingsite. The geochemical analyses report that these basaltic flows contain characteristics of rift basalts. The rocks have a normative olivine values from 5.78 to 27.26 and nepheline values from 0 to 2.34. In the TAS diagram the samples straddle the join between basalt and trachy-basalt, reflecting a high K2O content. The Mg# average is 0.297, a value that suggests that the basalts do not come from a primitive magma. The basalts have high values of Ba (945-1334 ppm), Cu (54-147 ppm), and Zn (123-615 ppm). The contents of Rb (23-57 ppm), Sr (659-810 ppm), Y (26-33 ppm), Zr (148-217 ppm) and Cr (79-98 ppm) are characteristics of rift basalts. Using discrimination diagrams, the basalts plot in the field of within plate, supporting the rifting origin. Outcrops of other basalts, at about 80 to 100 km to the east of the study area, Lomas El

  9. What Are Probability Surveys? (United States)

    The National Aquatic Resource Surveys (NARS) use probability-survey designs to assess the condition of the nation’s waters. In probability surveys (also known as sample-surveys or statistical surveys), sampling sites are selected randomly.

  10. Geochemical evaluation of CO2 injection into storage reservoirs based on case-studies in The Netherlands

    NARCIS (Netherlands)

    Tambach, T.; Koenen, M.; Bergen, F. van


    Over the past few years several geochemical evaluations of CO2 storage in Dutch potential reservoirs are carried out, including predictions of the short- and long-term impact of CO2 on the reservoir using geochemical modelling. The initial mineralogy of the reservoir is frequently obtained from core

  11. Evaluation of the Single Dilute (0.43 M) Nitric Acid Extraction to Determine Geochemically Reactive Elements in Soil

    NARCIS (Netherlands)

    Groenenberg, Jan E.; Römkens, Paul F.A.M.; Zomeren, van André; Rodrigues, S.M.; Comans, Rob N.J.


    Recently a dilute nitric acid extraction (0.43 M) was adopted by ISO (ISO-17586:2016) as standard for extraction of geochemically reactive elements in soil and soil like materials. Here we evaluate the performance of this extraction for a wide range of elements by mechanistic geochemical modeling

  12. Regional Geochemical Results from the Reanalysis of NURE Stream Sediment Samples - Eagle 3? Quadrangle, East-Central Alaska (United States)

    Crock, J.G.; Briggs, P.H.; Gough, L.P.; Wanty, R.B.; Brown, Z.A.


    This report presents reconnaissance geochemical data for a cooperative study in the Fortymile Mining District, east-central Alaska, initiated in 1997. This study has been funded by the U.S. Geological Survey (USGS) Mineral Resources Program. Cooperative funds were provided from various State of Alaska sources through the Alaska Department of Natural Resources. Results presented here represent the initial reconnaissance phase for this multidisciplinary cooperative study. In this phase, 239 sediment samples from the Eagle 3? Quadrangle of east-central Alaska, which had been collected and analyzed for the U.S. Department of Energy's National Uranium Resource Evaluation program (NURE) of the 1970's (Hoffman and Buttleman, 1996; Smith, 1997), are reanalyzed by newer analytical methods that are more sensitive, accurate, and precise (Arbogast, 1996; Taggart, 2002). The main objectives for the reanalysis of these samples were to establish lower limits of determination for some elements and to confirm the NURE data as a reliable predictive reconnaissance tool for future studies in Alaska's Eagle 3? Quadrangle. This study has wide implications for using the archived NURE samples and data throughout Alaska for future studies.

  13. Geochemical Data for Samples Collected in 2008 Near the Concealed Pebble Porphyry Cu-Au-Mo Deposit, Southwest Alaska (United States)

    Fey, David L.; Granitto, Matthew; Giles, Stuart A.; Smith, Steven M.; Eppinger, Robert G.; Kelley, Karen D.


    In the summer of 2007, the U.S. Geological Survey (USGS) began an exploration geochemical research study over the Pebble porphyry copper-gold-molybdenum deposit. This report presents the analytical data collected in 2008. The Pebble deposit is world class in size, and is almost entirely concealed by tundra, glacial deposits, and post-Cretaceous volcanic rocks. The Pebble deposit was chosen for this study because it is concealed by surficial cover rocks, is relatively undisturbed (except for exploration company drill holes), is a large mineral system, and is fairly well-constrained at depth by the drill hole geology and geochemistry. The goals of this study are to 1) determine whether the concealed deposit can be detected with surface samples, 2) better understand the processes of metal migration from the deposit to the surface, and 3) test and develop methods for assessing mineral resources in similar concealed terrains. The analytical data are presented as an integrated Microsoft Access 2003 database and as separate Excel files.

  14. Survey Expectations


    Martin Weale


    This paper focusses on survey expectations and discusses their uses for testing and modeling of expectations. Alternative models of expectations formation are reviewed and the importance of allowing for heterogeneity of expectations is emphasized. A weak form of the rational expectations hypothesis which focusses on average expectations rather than individual expectations is advanced. Other models of expectations formation, such as the adaptive expectations hypothesis, are briefly discussed. ...

  15. Survey Expectations


    Pesaran, M.H.; Weale, M.


    This paper focuses on survey expectations and discusses their uses for testing and modeling of expectations. Alternative models of expectations formation are reviewed and the importance of allowing for heterogeneity of expectations is emphasized. A weak form of the rational expectations hypothesis which focuses on average expectations rather than individual expectations is advanced. Other models of expectations formation, such as the adaptive expectations hypothesis, are briefly discussed. Te...

  16. Survey expectations


    Pesaran, Mohammad Hashem; Weale, Martin R.


    This paper focuses on survey expectations and discusses their uses for testing and modeling of expectations. Alternative models of expectations formation are reviewed and the importance of allowing for heterogeneity of expectations is emphasized. A weak form of the rational expectations hypothesis which focuses on average expectations rather than individual expectations is advanced. Other models of expectations formation, such as the adaptive expectations hypothesis, are briefly discussed. Te...

  17. Multifractal interpolation and spectrum-area fractal modeling of stream sediment geochemical data: Implications for mapping exploration targets (United States)

    Parsa, Mohammad; Maghsoudi, Abbas; Yousefi, Mahyar; Carranza, Emmanuel John M.


    The spectrum-area (S-A) fractal model is a powerful tool for decomposition of complex anomaly patterns of gridded geochemical data. Ordinary moving average interpolation techniques are commonly being used for gridding geochemical data; however, these methods suffer from two major drawbacks of (1) ignoring the locally high values and (2) smoothing the interpolated surface. Multifractal moving average interpolation methods have been developed to overcome the shortcomings of ordinary moving average methods. This study seeks to compare two sets of multifractal and ordinary gridded geochemical data using success rate curves and applies the S-A fractal model to decompose anomalous geochemical patterns. A set of stream sediment geochemical data in Ahar area, NW Iran, was used as a case study. Then, a mineralization-related multi-element geochemical signature was gridded by ordinary and multifractal approaches and considered for further analyses. The S-A fractal method was applied to decompose anomaly and background components of the resultant multi-element geochemical signature. Exploration targets were delimited and further evaluated using two bivariate statistical procedures of Student's t-value and normalized density index. The results revealed that (a) application of multifractal gridded data enhances the predicting ability of geochemical signatures, (b) application of S-A fractal model on multifractal gridded data allows for superior discrimination of geochemical anomalies, and (c) the multi-element geochemical anomalies in the Ahar area related to porphyry-Cu deposits were properly delineated through sequence application of multifractal interpolation and S-A fractal model.

  18. Surveying Education

    DEFF Research Database (Denmark)

    Enemark, Stig


    In relation to surveying education there is one big question to be asked: Is the role of the surveyors changing? In a global perspective the answer will be "Yes". There is a big swing that could be entitled "From Measurement to Management". This does not imply that measurement is no longer a rele...... on an efficient interaction between education, research, and professional practice.......In relation to surveying education there is one big question to be asked: Is the role of the surveyors changing? In a global perspective the answer will be "Yes". There is a big swing that could be entitled "From Measurement to Management". This does not imply that measurement is no longer....... In surveying education there are a range of other challenges to be faced. These relate to the focus on learning to learn; the need for flexible curriculum to deal with constant change; the move towards introducing virtual academy; the demand for creating a quality culture; and the perspective of lifelong...

  19. Geochemical constraints on the petrogenesis of basalts from eastern Jiangnan orogen, South China

    Institute of Scientific and Technical Information of China (English)

    唐红峰; 周新民


    The basalts crop out widely in the eastern part of late Proterozoic Jiangnan orogen. In terms of their petrographical and geochemical characteristics, they can be divided into two distinct types: low- and high-Ti basalts. They crystallized from the magmas derived from the depleted upper mantle differing in partial melting degree.

  20. Understanding Geochemical Impacts of Carbon Dioxide Leakage from Carbon Capture and Sequestration (United States)

    US EPA held a technical Geochemical Impact Workshop in Washington, DC on July 10 and 11, 2007 to discuss geological considerations and Area of Review (AoR) issues related to geologic sequestration (GS) of Carbon Dioxide (CO2). Seventy=one (71) representatives of the electric uti...

  1. Characterization of primary geochemical haloes for gold exploration at the Huanxiangwa gold deposit, China

    NARCIS (Netherlands)

    Wang, Changming; Carranza, Emmanuel John M.; Zhang, Shouting; Zhang, Jing; Liu, Xiaoji Liu; Zhang, Da; Sun, Xiang; Duan, Cunji


    Recognition of primary geochemical haloes is one of the most important tools for exploring undiscovered mineral resources. This tool is being routinely applied in exploration programs at the Huanxiangwa gold deposit, Xiong'er Mountains, China. Sampling of unweathered rock for multi-element analysis

  2. Geochemical indicators for use in the computation of critical loads and dynamic risk assessments

    NARCIS (Netherlands)

    Vries, de W.; Posch, M.; Sverdrup, H.U.; Larssen, T.; Wit, H.A.; Bobbink, R.; Hettelingh, J.P.


    This chapter provides an overview of geochemical indicators for nitrogen (N), acidity, and metals in soil and water (soil solution, ground water and surface water) in view of their impacts on different endpoints (tree growth/health, human health, soil biodiversity etc.). Relevant indicators for N ar

  3. Geochemical study of volcanic and associated granitic rocks from Endau Rompin, Johor, Peninsular Malaysia

    Indian Academy of Sciences (India)

    Azman A Ghani; Ismail Yusoff; Meor Hakif Amir Hassan; Rosli Ramli


    Geochemical studies and modelling show that both volcanic and granitic magmas from the western part of the Johor National Park, Endau Rompin are different and probably have different sources. The geochemical plot suggests that both dacite/rhyolite and andesite probably have a common origin as in many of the geochemical plots, these two groups form a similar trend. Volcanic rocks have a transitional geochemical character between tholeiite and calc alkaline on a Y versus Zr plot. (La/Yb)N versus La and TiO2 versus Zr modelling show that the crystallization of both granitic and volcanic magmas are controlled by a different set of minerals. The rare earth elements (REE) patterns of some of the granite and volcanic samples have pronounced negative Eu anomaly indicating plagioclase fractionation. The difference between both profiles is that the granite samples show a concave shape profile which is consistent with liquids produced by partial melting of quartz feldspathic rocks containing amphibole among the residual phase. Both magmas were generated at a different time during the subduction of Sibumasu beneath the Indochina blocks.

  4. Levels and geochemical fractions of Cd, Pb and Zn in valley bottom ...

    African Journals Online (AJOL)



    Oct 6, 2008 ... of these metals are related to the solubility of the geochemical forms and that the decrease in the order ... Correlation among species of each metal indicates a dynamic .... and chemical species of cadmium, lead and zinc in six .... meter using Buck scientific AGW AAS, AES MODEL 2004 operated according ...

  5. Estimation of Supraglacial Dust and Debris Geochemical Composition via Satellite Reflectance and Emissivity (United States)

    Casey, Kimberly Ann; Kaab, Andreas


    We demonstrate spectral estimation of supraglacial dust, debris, ash and tephra geochemical composition from glaciers and ice fields in Iceland, Nepal, New Zealand and Switzerland. Surface glacier material was collected and analyzed via X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD) for geochemical composition and mineralogy. In situ data was used as ground truth for comparison with satellite derived geochemical results. Supraglacial debris spectral response patterns and emissivity-derived silica weight percent are presented. Qualitative spectral response patterns agreed well with XRF elemental abundances. Quantitative emissivity estimates of supraglacial SiO2 in continental areas were 67% (Switzerland) and 68% (Nepal), while volcanic supraglacial SiO2 averages were 58% (Iceland) and 56% (New Zealand), yielding general agreement. Ablation season supraglacial temperature variation due to differing dust and debris type and coverage was also investigated, with surface debris temperatures ranging from 5.9 to 26.6 C in the study regions. Applications of the supraglacial geochemical reflective and emissive characterization methods include glacier areal extent mapping, debris source identification, glacier kinematics and glacier energy balance considerations.

  6. Geochemical assessment of nuclear waste isolation. Report of activities during fiscal year 1982

    Energy Technology Data Exchange (ETDEWEB)


    The status of the following investigations is reported: canister/overpack-backfill chemical interactions and mechanisms; backfill and near-field host rock chemical interactions mechanisms; far-field host rock geochemical interactions; verification and improvement of predictive algorithms for radionuclide migration; and geologic systems as analogues for long-term radioactive waste isolation.

  7. Geochemical landscape strategy in monitoring the areas contaminated by the Chernobyl radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Korobova, E.M.; Linnik, V.G. (Department of Geoinformation Investigations, Russian Scientific-Practical and Expert-Analytical Centre (RNEC), Moscow (Russian Federation))


    The Chernobyl accident led to radionuclide contamination of vast areas that now need to be monitored; the development of a regional land use strategy is now needed. Landscape geochemistry enables us to structure, classify and map the environmental factors responsible for the redistribution of radionuclides (i.e. soil-forming rocks and soil properties, vegetation cover, types of ground water migration, and vertical and lateral geochemical barriers). Combined with land use information, regional geochemical landscape maps serve as the basis to map in toposequence conditions of mass migration and accumulation in natural and cultivated landscapes. Such mapping makes it easier to choose representative monitoring sites. This type of mapping is also helpful to interrelate and extrapolate the data already obtained on radionuclides' environmental migration for different groups of geochemical landscapes with similar types of contamination, migration and accumulation patterns. A geochemical landscape approach is demonstrated using the example of part of the Bryansk region (Russia), which is considerably contaminated with [sup 134]Cs and [sup 137]Cs.

  8. Geochemical modelling of hydrogen gas migration in an unsaturated bentonite buffer

    NARCIS (Netherlands)

    Sedighi, M.; Thomas, H.R.; Al Masum, S.; Vardon, P.J.; Nicholson, D.; Chen, Q.


    This paper presents an investigation of the transport and fate of hydrogen gas through compacted bentonite buffer. Various geochemical reactions that may occur in the multiphase and multicomponent system of the unsaturated bentonite buffer are considered. A reactive gas transport model, developed

  9. Spatial analysis and modelling of glaciogenic geochemical dispersion - Implication for mineral exploration in Finland (United States)

    Sarala, Pertti; Nykänen, Vesa


    Spatial modelling for prospectivity mapping involves the integration of various geoscientific digital map data. It is essential that the quality of data is high class and that the geological processes involved are well understood. Effects of glacial dynamics and glaciogenic geochemical dispersion need to be taken into consideration when using till geochemistry as one of such input dataset for prospectivity modelling. This paper investigates this issue by developing a fuzzy logic prospectivity model that integrates airborne geophysical data with two different till geochemical datasets. First we use the original geochemical sample set and secondly a spatially corrected dataset that is based on the knowledge of glacial dynamics on the regional scale within the study area. The effect of this correction is tested by comparing the modelling results of both cases using the receiver operating characteristics (ROC) technique to validate the models by using the location of known gold deposits represented by exploration drilling. This study confirms that by taking into consideration the transport caused by the glaciation we can significantly improve the performance of a prospectivity model using till geochemical data.

  10. Geochemical baseline level and function and contamination of phosphorus in Liao River Watershed sediments of China. (United States)

    Liu, Shaoqing; Wang, Jing; Lin, Chunye; He, Mengchang; Liu, Xitao


    The quantitative assessment of P contamination in sediments is a challenge due to sediment heterogeneity and the lacking of geochemical background or baseline levels. In this study, a procedure was proposed to determine the average P background level and P geochemical baseline level (GBL) and develop P geochemical baseline functions (GBF) for riverbed sediments of the Liao River Watershed (LRW). The LRW has two river systems - the Liao River System (LRS) and the Daliao River System (DRS). Eighty-eight samples were collected and analyzed for P, Al, Fe, Ca, organic matter, pH, and texture. The results show that Fe can be used as a better particle-size proxy to construct the GBF of P (P (mg/kg) = 39.98 + 166.19 × Fe (%), R(2) = 0.835, n = 66). The GBL of P was 675 mg/kg, while the average background level of P was 355 mg/kg. Noting that many large cities are located in the DRS watershed, most of the contaminated sites were located within the DRS and the riverbed sediments were more contaminated by P in the DRS watershed than in the LRS watershed. The geochemical background and baseline information of P are of great importance in managing P levels within the LRW.

  11. Microscale geochemical gradients in Hanford 300 Area sediment biofilms and influence of uranium. (United States)

    Nguyen, Hung Duc; Cao, Bin; Mishra, Bhoopesh; Boyanov, Maxim I; Kemner, Kenneth M; Fredrickson, Jim K; Beyenal, Haluk


    The presence and importance of microenvironments in the subsurface at contaminated sites were suggested by previous geochemical studies. However, no direct quantitative characterization of the geochemical microenvironments had been reported. We quantitatively characterized microscale geochemical gradients (dissolved oxygen (DO), H(2), pH, and redox potential) in Hanford 300A subsurface sediment biofilms. Our results revealed significant differences in geochemical parameters across the sediment biofilm/water interface in the presence and absence of U(VI) under oxic and anoxic conditions. While the pH was relatively constant within the sediment biofilm, the redox potential and the DO and H(2) concentrations were heterogeneous at the microscale (<500-1000 μm). We found microenvironments with high DO levels (DO hotspots) when the sediment biofilm was exposed to U(VI). On the other hand, we found hotspots (high concentrations) of H(2) under anoxic conditions both in the presence and in the absence of U(VI). The presence of anoxic microenvironments inside the sediment biofilms suggests that U(VI) reduction proceeds under bulk oxic conditions. To test this, we operated our biofilm reactor under air-saturated conditions in the presence of U(VI) and characterized U speciation in the sediment biofilm. U L(III)-edge X-ray absorption spectroscopy (XANES and EXAFS) showed that 80-85% of the U was in the U(IV) valence state.

  12. Complex burrows of the mud shrimp Callianassa truncata and their geochemical impact in the sea bed

    DEFF Research Database (Denmark)

    Ziebis, W.; Forster, S.; Huettel, M.;


    ). Here we report the use of a diver observatory within the seabed, along with in situ measurements, to assess the geochemical impact of the mud-shrimp Callianassa truncata Giard and Bonnier (Decapoda, Thalassinidea), a species that commonly inhabits sandy sediments in the Mediterranean sea....

  13. Geochemical modelling of hydrogen gas migration in an unsaturated bentonite buffer

    NARCIS (Netherlands)

    Sedighi, M.; Thomas, H.R.; Al Masum, S.; Vardon, P.J.; Nicholson, D.; Chen, Q.


    This paper presents an investigation of the transport and fate of hydrogen gas through compacted bentonite buffer. Various geochemical reactions that may occur in the multiphase and multicomponent system of the unsaturated bentonite buffer are considered. A reactive gas transport model, developed wi

  14. Interpretation of heavy metal speciation in sequential extraction using geochemical modelling

    NARCIS (Netherlands)

    Cui, Yanshan; Weng, Liping


    Environmental context Heavy metal pollution is a worldwide environmental concern, and the risk depends not only on their total concentration, but also on their chemical speciation. Based on state-of-the-art geochemical modelling, we pinpoint the heavy metal pools approached by the widely used seq

  15. Geochemical modelling of hydrogen gas migration in an unsaturated bentonite buffer

    NARCIS (Netherlands)

    Sedighi, M.; Thomas, H.R.; Al Masum, S.; Vardon, P.J.; Nicholson, D.; Chen, Q.


    This paper presents an investigation of the transport and fate of hydrogen gas through compacted bentonite buffer. Various geochemical reactions that may occur in the multiphase and multicomponent system of the unsaturated bentonite buffer are considered. A reactive gas transport model, developed wi

  16. Secondary geochemical reactions in hydrothermal energy harnessing; Geochemische Folgereaktionen bei der hydrogeothermalen Energiegewinnung

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, M.


    This thesis is in six parts: description of geothermal energy harnessing, analytics, geochemical-thermodynamic modellings, experimental investigations, discussion of results, summary. (HW) [Deutsch] Die vorliegende Dissertationsschrift gliedert sich in 6 Teile: - Beschreibung der geothermischen Energienutzung - Analytik - geochemische-thermodynamische Modellierungen - experimentelle Untersuchungen - Diskussion der Ergebnisse - Zusammenfassung. (HW)

  17. Organic and inorganic geochemical aspects of Mediterranean Late Quaternary sapropels and Messinian evaporitic deposits

    NARCIS (Netherlands)

    Haven, H.L. ten


    This thesis describes the results of organic and inorganic geochemical investigations obtained for samples collected from the eastern Mediterranean sea floor and from Italy. The samples vary in age from the Late Miocene up to the Holocene. The environmental conditions prevailing during deposition of

  18. The potential of lacquer-peel soil profiles for palaeo-geochemical analysis using XRF analysis

    NARCIS (Netherlands)

    Arnoldussen, Stijn; van Os, B.J.H.


    This paper discusses the suitability of hand-held XRF analysis to extract palaeo-geochemical information from lacquer-peel soil sections that have been taken to document pedological information at geological and archaeological sites. This not only allows the study of sections from archaeological and

  19. Petrographic and geochemical composition of kerogen in the Furongian (U. Cambrian) Alum Shale, central Sweden

    DEFF Research Database (Denmark)

    Sanei, H.; Petersen, H. I.; Schovsbo, N. H.;


    This paper presents an integrated geochemical and petrological study of the Hällekis-1 core from the Furongian (upper Cambrian) Alum shales in central Sweden to characterise organic matter composition, depositional environment, and potential hydrocarbon generation capability. The results show tha...

  20. Geochemical processes at a fresh/seawater interface in a shallow sandy aquifer

    DEFF Research Database (Denmark)

    Andersen, Martin Søgaard; Iversen, Vibeke Margrethe Nyvang; Postma, Diederik Jan


    Chemical processes in a natural fresh-/seawater mixing zone were studied in a shallow sandy aquifer. The dominant redox-processes are sulfate reduction and methanogenesis. Methanogenesis produces CO2, which causes calcite dissolution. The produced calcium induces ion exchange with sodium. The final...... result of these interactions between different types of geochemical processes is an anoxic groundwater enriched in bicarbonate and sodium....

  1. Geochemical and Rheological Constraints on the Dynamics of the Oceanic Upper Mantle (United States)


    or in part is permitted for any purpose of the United States Government . This thesis should be cited as: Jessica Mendelsohn Warren, 2007. Geochemical...Wilshire, H. G., Nielson, J. E., 1991. Intrinsic Nd, Pb and Sr isotopic heterogeneities exhibited by the Lherz Alpine Peridotite Massif, French Pyrenees

  2. Estimation of Supraglacial Dust and Debris Geochemical Composition via Satellite Reflectance and Emissivity

    Directory of Open Access Journals (Sweden)

    Kimberly Casey


    Full Text Available We demonstrate spectral estimation of supraglacial dust, debris, ash and tephra geochemical composition from glaciers and ice fields in Iceland, Nepal, New Zealand and Switzerland. Surface glacier material was collected and analyzed via X-ray fluorescence spectroscopy (XRF and X-ray diffraction (XRD for geochemical composition and mineralogy. In situ data was used as ground truth for comparison with satellite derived geochemical results. Supraglacial debris spectral response patterns and emissivity-derived silica weight percent are presented. Qualitative spectral response patterns agreed well with XRF elemental abundances. Quantitative emissivity estimates of supraglacial SiO2 in continental areas were 67% (Switzerland and 68% (Nepal, while volcanic supraglacial SiO2 averages were 58% (Iceland and 56% (New Zealand, yielding general agreement. Ablation season supraglacial temperature variation due to differing dust and debris type and coverage was also investigated, with surface debris temperatures ranging from 5.9 to 26.6 C in the study regions. Applications of the supraglacial geochemical reflective and emissive characterization methods include glacier areal extent mapping, debris source identification, glacier kinematics and glacier energy balance considerations.

  3. From extreme pH to extreme temperature: An issue in honor of the geochemical contributions of Kirk Nordstrom, USGS hydrogeochemist (United States)

    Campbell, Kate M.; Verplanck, Philip L.; McCleskey, R. Blaine; Alpers, Charles N.


    This special issue of Applied Geochemistry honors Dr. D. Kirk Nordstrom, and his influential career spent primarily at the U.S. Geological Survey (USGS). This issue does not herald his retirement or other significant career milestone, but serves as a recognition of the impact his work has had on the field of geochemistry in general. This special issue grew from a symposium in Kirk’s honor (affectionately dubbed “Kirkfest”) at the Geological Society of America’s annual meeting in Denver, Colorado, USA, during October 2013. At GSA, 27 talks and 35 posters showed how Kirk’s work has influenced a wide range of current hydrogeochemical research, from geothermal processes to acid mine drainage to geochemical modeling. The breadth of his knowledge and his many contributions to the published literature have left an indelible mark on the field of geochemistry, and this special issue is a tribute to his experience and contributions.

  4. A geostatistical method applied to the geochemical study of the Chichinautzin Volcanic Field in Mexico (United States)

    Robidoux, P.; Roberge, J.; Urbina Oviedo, C. A.


    The origin of magmatism and the role of the subducted Coco's Plate in the Chichinautzin volcanic field (CVF), Mexico is still a subject of debate. It has been established that mafic magmas of alkali type (subduction) and calc-alkali type (OIB) are produced in the CVF and both groups cannot be related by simple fractional crystallization. Therefore, many geochemical studies have been done, and many models have been proposed. The main goal of the work present here is to provide a new tool for the visualization and interpretation of geochemical data using geostatistics and geospatial analysis techniques. It contains a complete geodatabase built from referred samples over the 2500 km2 area of CVF and its neighbour stratovolcanoes (Popocatepetl, Iztaccihuatl and Nevado de Toluca). From this database, map of different geochemical markers were done to visualise geochemical signature in a geographical manner, to test the statistic distribution with a cartographic technique and highlight any spatial correlations. The distribution and regionalization of the geochemical signatures can be viewed in a two-dimensional space using a specific spatial analysis tools from a Geographic Information System (GIS). The model of spatial distribution is tested with Linear Decrease (LD) and Inverse Distance Weight (IDW) interpolation technique because they best represent the geostatistical characteristics of the geodatabase. We found that ratio of Ba/Nb, Nb/Ta, Th/Nb show first order tendency, which means visible spatial variation over a large scale area. Monogenetic volcanoes in the center of the CVF have distinct values compare to those of the Popocatepetl-Iztaccihuatl polygenetic complex which are spatially well defined. Inside the Valley of Mexico, a large quantity of monogenetic cone in the eastern portion of CVF has ratios similar to the Iztaccihuatl and Popocatepetl complex. Other ratios like alkalis vs SiO2, V/Ti, La/Yb, Zr/Y show different spatial tendencies. In that case, second

  5. Evaluation of Geochemical Fracture Conductivity Alterations in Shale under Laboratory Conditions (United States)

    Radonjic, M.; Olabode, A.


    In large scale subsurface injection of carbondioxide as obtainable in carbon sequestration programs and in environmentally friendly hydraulic fracturing processes (using supercritical CO2), rock-fluid interaction can affect reservoir and seal rocks properties which are essential in monitoring the progress of these operations. The mineralogical components of sedimentary rocks are geochemically active particularly under enormous earth stresses. While geomechanical properties such as rock stiffness, Poisson's ratio and fracture geometry largely govern fluid flow characteristics in deep fractured formations, the effect of mineralization can lead to flow impedance in the presence of favorable geochemical and thermodynamic conditions. Experimental works which employed the use of analytical tools such as ICP-OES, XRD, SEM/EDS, TOC and BET techniques in investigating diagenetic and micro-structural properties of crushed shale caprock/CO2-brine system concluded that net precipitation reaction processes can affect the distribution of petrophysical nanopores in the shale as a result of rock-fluid interactions. Simulation results previously reported, suggest that influx-induced mineral dissolution/precipitation reactions within clay-based sedimentary rocks can continuously close micro-fracture networks, though injection pressure and effective-stress transformation first rapidly expand these fractures. This experimental modelling research investigated the impact of in-situ geochemical precipitation on conductivity of fractures under geomechanical stress conditions. Conductivity is measured as differential-pressure drop equivalence, using a pressure pulse-decay liquid permeametry/core flooding system, as geochemically saturated-fluid is transported through composite cores with embedded micro-tubings that mimic fractures. The reactive fluid is generated from crushed shale rocks of known mineralogical composition when flooded with aqueous CO2 at elevated temperature and pressure

  6. An overview of the geochemical code MINTEQ: Applications to performance assessment for low-level wastes

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, S.R.; Opitz, B.E.; Graham, M.J.; Eary, L.E.


    The MINTEQ geochemical computer code, developed at the Pacific Northwest Laboratory (PNL), integrates many of the capabilities of its two immediate predecessors, MINEQL and WATEQ3. The MINTEQ code will be used in the Special Waste Form Lysimeters-Arid program to perform the calculations necessary to simulate (model) the contact of low-level waste solutions with heterogeneous sediments of the interaction of ground water with solidified low-level wastes. The code can calculate ion speciation/solubilitya, adsorption, oxidation-reduction, gas phase equilibria, and precipitation/dissolution of solid phases. Under the Special Waste Form Lysimeters-Arid program, the composition of effluents (leachates) from column and batch experiments, using laboratory-scale waste forms, will be used to develop a geochemical model of the interaction of ground water with commercial, solidified low-level wastes. The wastes being evaluated include power-reactor waste streams that have been solidified in cement, vinyl ester-styrene, and bitumen. The thermodynamic database for the code was upgraded preparatory to performing the geochemical modeling. Thermodynamic data for solid phases and aqueous species containing Sb, Ce, Cs, or Co were added to the MINTEQ database. The need to add these data was identified from the characterization of the waste streams. The geochemical model developed from the laboratory data will then be applied to predict the release from a field-lysimeter facility that contains full-scale waste samples. The contaminant concentrations migrating from the waste forms predicted using MINTEQ will be compared to the long-term lysimeter data. This comparison will constitute a partial field validation of the geochemical model.

  7. Long-term geochemical evaluation of the coastal Chicot aquifer system, Louisiana, USA (United States)

    Borrok, David M.; Broussard, Whitney P.


    Groundwater is increasingly being overdrafted in the Gulf and Atlantic Coastal regions of the United States. Geochemical data associated with groundwater in these aquifers can provide important information on changes in salinity, recharge, and reaction pathways that can be used to improve water management strategies. Here we evaluated long-term geochemical changes associated with the 23,000 km2 Chicot aquifer system in Louisiana, USA. The Chicot aquifer is currently being overdrafted by about 1,320,000 m3 per day. We compiled selected bulk geochemical data from samples collected from 20 wells in the Chicot aquifer from 1993 to 2015. Oxygen and hydrogen isotope measurements were additionally completed for the 2014 samples. We identified three zones of groundwater with distinctive geochemical character; (1) A groundwater recharge zone in the northern part of the study area with low pH, low salinity, and low temperature relative to other groundwater samples, (2) a groundwater recharge zone in the southeastern part of the study area with low temperature, high alkalinity, and higher Ca and Mg concentrations compared to the other groundwater samples, and (3) groundwater in the southwestern part of the aquifer system with high salinity, high temperature, and a ∼1:1 Na/Cl ratio. The geochemistry of these regions has been relatively stable over the last ∼20 years. However, in the drought year of 2011, the estimated extent of zones with elevated salinity increased substantially. Geochemical evidence suggests that there was increased infiltration of deeper, more salt-rich waters into the shallower Chicot aquifer.

  8. Geochemical conditions and the occurrence of selected trace elements in groundwater basins used for public drinking-water supply, Desert and Basin and Range hydrogeologic provinces, 2006-11: California GAMA Priority Basin Project (United States)

    Wright, Michael T.; Fram, Miranda S.; Belitz, Kenneth


    The geochemical conditions, occurrence of selected trace elements, and processes controlling the occurrence of selected trace elements in groundwater were investigated in groundwater basins of the Desert and Basin and Range (DBR) hydrogeologic provinces in southeastern California as part of the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA PBP is designed to provide an assessment of the quality of untreated (raw) groundwater in the aquifer systems that are used for public drinking-water supply. The GAMA PBP is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory.

  9. Multiple Surveys of Students and Survey Fatigue (United States)

    Porter, Stephen R.; Whitcomb, Michael E.; Weitzer, William H.


    This chapter reviews the literature on survey fatigue and summarizes a research project that indicates that administering multiple surveys in one academic year can significantly suppress response rates in later surveys. (Contains 4 tables.)

  10. A geochemical survey of thermal springs in western part of Republic of Yemen and their geothermometric characteristics

    Institute of Scientific and Technical Information of China (English)

    Hazaea Mohammed; HU Ke


    The high-mineral contents of some thermal waters are believed to have medicinal properties. Numerous spas and bathhouses might be built at these hot springs to take advantage of theses supposed healing properties such as skin diseases, rheumatism and so on. This paper is to find thermal reservoir and to classify the kinds of water. The majority of thermal springs are found discharging from igneous centers of Tertiary and Quaternary volcanic fields of the western Yemen (research area). Structurally these volcanisms are connected to N-NW faults that are parallel to the main Red Sea trend. Temperature and pH values of the thermal spring range 37℃~96℃, and 6.3 ~8.7 respectively. The Yemeni thermal waters indicate high variability in composition since they are ofNa (K) -C1, Na-HCO3 and Ca (Mg) -SO4 types, whereas the surficial waters have the typical worldwide Ca (Mg) -HCO3 composition. Different liquid phase geothermometers,such as SiO2, K2/Mg and Na/K. Estimated reservoir temperatures ranging 70 ~ 140℃ perform equilibrium temperature evaluation of the thermal reservoirs.

  11. Infrastructure Survey 2011 (United States)

    Group of Eight (NJ1), 2012


    In 2011, the Group of Eight (Go8) conducted a survey on the state of its buildings and infrastructure. The survey is the third Go8 Infrastructure survey, with previous surveys being conducted in 2007 and 2009. The current survey updated some of the information collected in the previous surveys. It also collated data related to aspects of the…

  12. Geochemical and Isotopic (Sr, U) Tracing of Weathering Processes Controlling the Recent Geochemical Evolution of Soil Solutions in the Strengbach Catchment (Vosges, France) (United States)

    Chabaux, F. J.; Prunier, J.; Pierret, M.; Stille, P.


    The characterization of the present-day weathering processes controlling the chemical composition of waters and soils in natural ecosystems is an important issue to predict and to model the response of ecosystems to recent environmental changes. It is proposed here to highlight the interest of a multi-tracer geochemical approach combining measurement of major and trace element concentrations along with U and Sr isotopic ratios to progress in this topic. This approach has been applied to the small granitic Strengbah Catchment, located in the Vosges Mountain (France), used and equipped as a hydro-geochemical observatory since 1986 (Observatoire Hydro-Géochimique de l'Environnement; This study includes the analysis of major and trace element concentrations and (U-Sr) isotope ratios in soil solutions collected within two soil profiles located on two experimental plots of this watershed, as well as the analysis of soil samples and vegetation samples from these two plots The depth variation of elemental concentration of soil solutions confirms the important influence of the vegetation cycling on the budget of Ca, K, Rb and Sr, whereas Mg and Si budget in soil solutions are quasi exclusively controlled by weathering processes. Variation of Sr, and U isotopic ratios with depth also demonstrates that the sources and biogeochemical processes controlling the Sr budget of soil solutions is different in the uppermost soil horizons and in the deeper ones, and clearly influence by the vegetation cycling.

  13. Pilot study of the application of Tellus airborne radiometric and soil geochemical data for radon mapping. (United States)

    Appleton, J D; Miles, J C H; Green, B M R; Larmour, R


    The scope for using Tellus Project airborne gamma-ray spectrometer and soil geochemical data to predict the probability of houses in Northern Ireland having high indoor radon concentrations is evaluated, in a pilot study in the southeast of the province, by comparing these data statistically with in-house radon measurements. There is generally good agreement between radon maps modelled from the airborne radiometric and soil geochemical data using multivariate linear regression analysis and conventional radon maps which depend solely on geological and indoor radon data. The radon maps based on the Tellus Project data identify some additional areas where the radon risk appears to be relatively high compared with the conventional radon maps. One of the ways of validating radon maps modelled on the Tellus Project data will be to carry out additional indoor measurements in these areas.

  14. Element Geochemical Division of the Middle Segment of the Sanjiang(Three-River) Region

    Institute of Scientific and Technical Information of China (English)

    沈上越; 魏启荣; 莫宣学; 喻学惠; 曾普盛; 胡长寿


    This paper describes the aim and principle of element geochemical division, the source of samples and data processing, the choice of divisional indices and the division of index value ranges. According to the geological structures and characteristic values (the accumulated value of enrichment coefficient) of the mantle-type elements (KT) this region can be divided into seven geochemical zones, i.e., the Yangtze basement, the Yangtze cover, the Jinshajiang paleo-Tethys, the Lancangjiang paleo-Tethys, the Lanping Mesozoic basin, the Indosinian granite, and the Himalayan granite. Again in accordance with the different characteristic val ues of high field strength elements (HFSE) (KNb) or radiogenic elements (KTh) 16 geochemi cal sub-zones can be divided. Meanwhile, this paper also discusses the rules of variation in char acteristic value of the various sub-zones and points out the characteristics of enrichment of ore forming elements in some of the sub-zones.

  15. Geochemical and isotopic signatures for the identification of seawater intrusion in an alluvial aquifer

    Indian Academy of Sciences (India)

    Indu S Nair; S P Rajaveni; M Schneider; L Elango


    Seawater intrusion is one of the alarming processes that reduces the water quality and imperils the supply of freshwater in coastal aquifers. The region, north of the Chennai city, India is one such site affected by seawater intrusion. The objective of this study is to identify the extent of seawater intruded area by major geochemical and isotopic signatures. A total of 102 groundwater samples were collected and analysed for major and minor ions. Groundwater samples with electrical conductivity (EC) greater than 5000 S/cm and a river mouth sample were analyzed for Oxygen-18 (18O) and Deuterium (2H) isotopes to study their importance in monitoring seawater intrusion. The molar ratio of geochemical indicators and isotopic signatures suggests an intrusion up to a distance of 13 km from the sea as on March 2012 and up to 14.7 km during May 2012.

  16. Geochemical Characteristics of Oilfield Waters from the Turpan Depression,Xinjiang and Their Petroleum Geological Significance

    Institute of Scientific and Technical Information of China (English)

    李伟; 陈晓红; 等


    This paper,based on the fundamental inorganic chemical and organic geochemical characteristics of oilfield waters from the Turpan Depression,presents the contents of organic matter,the distribution of low-carbon fatty acids and the contents of aromatic hydrocarbons as well as their principal ultraviolet absorption spectral and fluorescence spectral characteristics in oilfield waters from different oil/gas-bearing areas.The oil/gas reservoirs in this depression are classified in terms of their conserving conditions.In additon,the paper also discusses the chemical characteristics of oilfield waters from different types of oil/gas reservoirs with an emphasis on the characteristics of their localization in the γNa/γCa-γN a/γCl correction diagram.On this basis it is attempted to expound the fundamental geochemical characteristics of oilfield waters from the Turpan Depression and their geological significance.

  17. A numerical procedure for geochemical compaction in the presence of discontinuous reactions (United States)

    Agosti, Abramo; Giovanardi, Bianca; Formaggia, Luca; Scotti, Anna


    The process by which rocks are formed from the burial of a fresh sediment involves the coupled effects of mechanical compaction and geochemical reactions. Both of them affect the porosity and permeability of the rock and, in particular, geochemical reactions can significantly alter them, since dissolution and precipitation processes may cause a structural transformation of the solid matrix. Often, the differential problems that arise from the modeling of these chemical reactions may present a discontinuous right hand side, where the discontinuity depends on the solution itself. In this work we have developed a numerical model to simulate this complex multi-physics problem by treating the discontinuous right hand side with a specially tailored event-driven numerical scheme. We show the performance of this strategy in terms of positivity and mass conservation, also in comparison with a more traditional approach that relies on a regularization of the discontinuous terms.

  18. Geochemical changes at the Permian–Triassic transition in Southern Alps and adjacent area: a review

    Directory of Open Access Journals (Sweden)

    Aymon Baud


    Full Text Available Compilation of the recent literature from the Southern Alps and adjacent area confirms the geochemical variations of unusual amplitudes during the Permian-Triassic boundary interval (PTBI. A great attention has been given to the negative δ13C anomaly within the Tesero Member close to the Permian-Triassic boundary. Very detailed geochemical works have been done on the scientific Gartnerkofel core (Gk-1 and on the Slovenian sections. Major minor and rare earth elements (REE data are reported and show a marked enrichment in alkaline metals and REE of some levels of the boundary interval. But recent studies show that the low Iridium anomalies and the Osmium and Helium isotopes anomalies lack the characteristics of a large extraterrestrial impact.

  19. Genesis and organic geochemical characteristics of the carbonaceous rock stratabound gold deposits, South China

    Institute of Scientific and Technical Information of China (English)

    胡凯; 翟建平; 刘英俊; 王鹤年; 张景荣; 贾蓉芬


    The organic matter of three different chronological major carbonaceous rock gold-bearing formations of South China (Middle Proterozoic Shangqiaoshan group of northeastern Jiangxi, Lower Cambrian Shuikou group of northern Guangxi and Devonian Shetianqiao group of eastern Hunan) and related carbonaceous stratabound gold deposits such as Jinshan, Longshui and Shixia deposits, respectively, has been characterized by organic geochemical techniques. These organic geochemical results show that the average total organic carbon (TOC) content of the three chronological carbonaceous rock gold-bearing formations of South China ranges from 0.15% to 1.56%. The thermal maturity of the organic matter of host rocks in the three gold-bearing formations is high. The micro-component of the organic matter of the host rocks consists primarily of solid bitumen and graphite. The organic carbon and gold of the host rocks appear to syndeposit in situ during the formation of the gold-bearing formations. The organic carbon played

  20. Petrologic and Geochemical Characteristics and Origin of Gusui Cherts,Guangdong Province,China

    Institute of Scientific and Technical Information of China (English)



    The characteristic structures of the Precambrian cherts from the Gusui section, Guangdong ,Chi-na, include bedded structure ,laminated structure ,massive structure and pseudobrecciated structure.The chert is characterized by consistently low abundance of TiO2,Al2O3 and most trace elements.Howevver ,it is enriched in Ba,As,Sb,Hg and Se.In Al-Fe-Mn ternary diagrams,it falls into the "hydrothermal field" .Correspondence analysis and factor analysis show that many elements show up in the factor that represents the leaching of country rocks by hydrothermal solutions,and are the very characteristic element association fo the geochemically anomalous South China basement.Petrologic and geochemical evidence suggests a hydrothermal origin for the chert.The chert may have been formed in a Precambrian fift or an extension zone developed within the Yunkai marginal geosyncline, with a fault system linking it to an unknown heat source at depth.

  1. Research and Application of New Methods to Oil-Gas Geochemical Exploration

    Institute of Scientific and Technical Information of China (English)


    Based on the results of researches and applications for many years, it has been discovered that new methods and techniques for geochemical exploration of oil and gas such as D C, altered carbonate, Hg in absorption phase, Ks, Fe2+, d 13C, fluorescence in two and three dimensions, and N2 and O2 in heat release can give full play in the following five fields: (1) optimization of the favourable target or hollow zones and structural zones in a region; (2) evaluation of oil traps and delineation of prospective oil and gas areas; (3) prediction of deep-seated oil-bearing horizons; (4) evaluation of the genesis of oil and gas geochemical anomalies and determination of the types of oil and gas accumulations; (5) forecast of the burial depths of oil and gas pools.

  2. Research on the Eco-Geochemical Effects of Black Shales in Pingli County, Shaanxi

    Institute of Scientific and Technical Information of China (English)

    方维萱; 兀鹏武; 黄转莹


    This paper presents the results of eco-geochemical research on black rock series en riched in metallic elements in Pingli County, Shaanxi Province, which lies at the northern mar gin of the Yangtze Platform. There is a suite of bone coal-bearing black carbonaceous rocks in the Cambrian Donghe Formation throughout the region. Soils in Pingli contain high metallic el ements derived from the bone coal and carbonaceous rocks. Edible plants growing in the soils contain high Se, Cu and Mo. Two case studies are documented. One is a black shale area with bone coal and Se enrichment, and the other is a black shale area with bone coal mine and cop per mineralization. Eco-geochemical effects of metallic element-rich black shales on plants are reported in this paper.

  3. Removal of iron interferences by solvent extraction for geochemical analysis by atomic-absorption spectrophotometry (United States)

    Zhou, L.; Chao, T.T.; Sanzolone, R.F.


    Iron is a common interferent in the determination of many elements in geochemical samples. Two approaches for its removal have been taken. The first involves removal of iron by extraction with methyl isobutyl ketone (MIBK) from hydrochloric acid medium, leaving the analytes in the aqueous phase. The second consists of reduction of iron(III) to iron(II) by ascorbic acid to minimize its extraction into MIBK, so that the analytes may be isolated by extraction. Elements of interest can then be determined using the aqueous solution or the organic extract, as appropriate. Operating factors such as the concentration of hydrochloric acid, amounts of iron present, number of extractions, the presence or absence of a salting-out agent, and the optimum ratio of ascorbic acid to iron have been determined. These factors have general applications in geochemical analysis by atomic-absorption spectrophotometry. ?? 1985.

  4. Mineralogical and Geochemical Investigations in the Perm State University (1916 – 2016

    Directory of Open Access Journals (Sweden)

    R. G. Iblaminov


    Full Text Available The history of foundation and development of mineralogical and geochemical sciences on the Mineralogy and Petrography Department of the Perm State University for 100 years is presented. The achievements in the alluvial mineralogy and nanomineralogy are characterised. Relationship of development in the area of geochemical research on early stage with the European scientific school is discussed. The next stage is characterized by transition to investigations of trace elements and usage of the modern analytic base for environmental geochemistry. Petrographic and lithologic investigations have become the base for paleotectonic reconstruction of the Western Urals area. The study of distribution of mineral resources has been conducted on the base of specific minerageodynamic concept. The principles of minerageodinamic investigation of oil and gas basins, and methodology of reservoir study using modern technology were developed. The contribution of individual scientists in development in different scientific areas is illustrated.

  5. Selected Geochemical Data for Modeling Near-Surface Processes in Mineral Systems (United States)

    Giles, Stuart A.; Granitto, Matthew; Eppinger, Robert G.


    The database herein was initiated, designed, and populated to collect and integrate geochemical, geologic, and mineral deposit data in an organized manner to facilitate geoenvironmental mineral deposit modeling. The Microsoft Access database contains data on a variety of mineral deposit types that have variable environmental effects when exposed at the ground surface by mining or natural processes. The data tables describe quantitative and qualitative geochemical analyses determined by 134 analytical laboratory and field methods for over 11,000 heavy-mineral concentrate, rock, sediment, soil, vegetation, and water samples. The database also provides geographic information on geology, climate, ecoregion, and site contamination levels for over 3,000 field sites in North America.

  6. Expected Geochemical and Mineralogical Properties of Meteorites from Mercury: Inferences from Messenger Data (United States)

    McCubbin, F. M.; McCoy, T. J.


    Meteorites from the Moon, Mars, and many types of asteroid bodies have been identified among our global inventory of meteorites, however samples of Mercury and Venus have not been identified. The absence of mercurian and venusian meteorites could be attributed to an inability to recognize them in our collections due to a paucity of geochemical information for Venus and Mercury. In the case of mercurian meteorites, this possibility is further supported by dynamical calculations that suggest mercurian meteorites should be present on Earth at a factor of 2-3 less than meteorites from Mars [1]. In the present study, we focus on the putative mineralogy of mercurian meteorites using data obtained from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, which has provided us with our first quantitative constraints on the geochemistry of planet Mercury. We have used the MESSENGER data to compile a list of mineralogical and geochemical characteristics that a meteorite from Mercury is likely to exhibit.

  7. A COMSOL-GEMS interface for modeling coupled reactive-transport geochemical processes (United States)

    Azad, Vahid Jafari; Li, Chang; Verba, Circe; Ideker, Jason H.; Isgor, O. Burkan


    An interface was developed between COMSOL MultiphysicsTM finite element analysis software and (geo)chemical modeling platform, GEMS, for the reactive-transport modeling of (geo)chemical processes in variably saturated porous media. The two standalone software packages are managed from the interface that uses a non-iterative operator splitting technique to couple the transport (COMSOL) and reaction (GEMS) processes. The interface allows modeling media with complex chemistry (e.g. cement) using GEMS thermodynamic database formats. Benchmark comparisons show that the developed interface can be used to predict a variety of reactive-transport processes accurately. The full functionality of the interface was demonstrated to model transport processes, governed by extended Nernst-Plank equation, in Class H Portland cement samples in high pressure and temperature autoclaves simulating systems that are used to store captured carbon dioxide (CO2) in geological reservoirs.

  8. Fate of inorganic contaminants post treatment of acid mine drainage by cryptocrystalline magnesite: Complimenting experimental results with a geochemical model

    CSIR Research Space (South Africa)

    Masindi, V


    Full Text Available This study assessed the fate of inorganic contaminants post treatment of acid mine drainage by cryptocrystalline magnesite. To accomplish that, neutralization and metal attenuation were evaluated and complemented with simulations using geochemical...

  9. A preliminary study on the geochemical environment for deep geological disposal of high level radioactive waste in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chun Soo; Bae, Dae Seok; Kim, Kyung Su; Koh, Yong Kwon; Park, Byoung Yun


    Geochemical study on the groundwater from crystalline rocks (granite and gneiss) for the deep geological disposal of high-level radioactive waste was carried out in order to elucidate the hydrogeochemical and isotope characteristics and geochemical evolution of the groundwater. Study areas are Jungwon, Chojeong, Youngcheon and Yusung for granite region, Cheongyang for gneiss region, and Yeosu for volcanic region. Groundwaters of each study areas weree sampled and analysed systematically. Groundwaters can be grouped by their chemistry and host rock. Origin of the groundwater was proposed by isotope ({sup 18}O, {sup 2}H, {sup 13}C, {sup 34}S, {sup 87}Sr, {sup 15}N) studies and the age of groundwater was inferred from their tritium contents. Based ont the geochemical and isotope characteristics, the geochemical evolutions of each types of groundwater were simulated using SOLVEQ/CHILLER and PHREEQC programs.

  10. Geochemical and diatom records of recent changes in depositional environment of a tropical wetland, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Pande, A.; Nayak, G.N.; Prasad, V.; PrakashBabu, C

    Two mudflat sediment cores collected from a sub-channel (S-61) and the main channel (S-60) of a tropical wetland, along central west coast of India, were investigated for recent changes in depositional environment using geochemical (sediment grain...

  11. The Agoudal (High Atlas Mountains, Morocco) Shattered Limestone: Petrographical and Geochemical Studies and Additional Evidence of Impact (United States)

    El Kerni, H.; Chennaoui Aoudjehane, H.; Marjanac, T.


    Agoudal impact structure shattered limestone and breccia are well studied and described using petrographical observations and geochemical analyses, and a new discovery of the magnesiwustite mineral as a further evidence of impact event.

  12. Relationship between pollen assemblages and organic geochemical proxies and the response to climate change in the Zhuye Lake sediments

    Institute of Scientific and Technical Information of China (English)

    Yu Li; XueHua Zhou; ChengQi Zhang; ZhuoLun Li; Yue Wang; NaiAng Wang


    This paper examines the relationship among organic geochemical proxies (TOC, C/N ratio andδ13C) and pollen assemblages in Zhuye Lake sediments since the Late Glacial. Results show that the reaction extent of organic geochemical proxies and pollen as-semblages to environment changes are different. Organic geochemical proxies are sensitive to overall environmental change, while pollen assemblages indicate detailed information of environmental change. For the entire sedimentary section (except the sand layer from the bottom of the section), when values of TOC, C/N ratio and total pollen concentrations are high,δ13C values are low, and vice versa. The different responses of organic geochemical proxies and pollen records in Zhuye Lake are mainly due to their different sensitivity and diverse influencing factors in different environmental conditions.

  13. Supraglacial dust and debris: geochemical compositions from glaciers in Svalbard, southern Norway, Nepal and New Zealand

    Directory of Open Access Journals (Sweden)

    K. A. Casey


    Full Text Available Alpine glacier samples were collected in four contrasting regions to measure supraglacial dust and debris geochemical composition and quantify regional variability. A total of 70 surface glacier ice, snow and debris samples were collected in Svalbard, southern Norway, Nepal and New Zealand. Trace elemental abundances in snow and ice samples were measured via inductively coupled plasma mass spectrometry (ICP-MS. Supraglacial debris mineral, bulk oxide and trace element composition were determined via X-ray diffraction (XRD and X-ray fluorescence spectroscopy (XRF. A total of 45 major, trace and rare earth elements and 10 oxide compound abundances are reported. Elemental abundances revealed sea salt aerosol and metal enrichment in Svalbard, low levels of crustal dust and marine influences to southern Norway, high crustal dust and anthropogenic enrichment in the Khumbu Himalayas, and sulfur and metals attributed to quiescent degassing and volcanic activity in northern New Zealand. Rare earth element and Al/Ti elemental ratios demonstrated distinct provenance of particulates in each study region. Ca/S elemental ratio data showed seasonal denudation in Svalbard and southern Norway. Ablation season atmospheric particulate transport trajectories were mapped in each of the study regions and suggest provenance pathways. The in situ data presented provides first-order glacier surface geochemical variability as measured in the four diverse alpine glacier regions. The surface glacier geochemical data set is available from the PANGAEA database at doi:10.1594/PANGAEA.773951. This geochemical surface glacier data is relevant to glaciologic ablation rate understanding as well as satellite atmospheric and land-surface mapping techniques currently in development.

  14. A Quantitative Geochemical Target for Modeling the Formation of the Earth and Moon (United States)

    Boyce, Jeremy W.; Barnes, Jessica J.; McCubbin, Francis M.


    The past decade has been one of geochemical, isotopic, and computational advances that are bringing the laboratory measurements and computational modeling neighborhoods of the Earth-Moon community to ever closer proximity. We are now however in the position to become even better neighbors: modelers can generate testable hypthotheses for geochemists; and geochemists can provide quantitive targets for modelers. Here we present a robust example of the latter based on Cl isotope measurements of mare basalts.

  15. Statistical analysis of iron geochemical data suggests limited late Proterozoic oxygenation


    Sperling, Erik; Wolock, Charles J.; Morgan, Alex S.; Gill, Benjamin C.; Kunzmann, Marcus,; Halverson, Galen P.; Macdonald, Francis Alexander; Knoll, Andrew Herbert; Johnston, David T.


    Sedimentary rocks deposited across the Proterozoic–Phanerozoic transition record extreme climate fluctuations, a potential rise in atmospheric oxygen or re-organization of the seafloor redox landscape, and the initial diversification of animals. It is widely assumed that the inferred redox change facilitated the observed trends in biodiversity. Establishing this palaeoenvironmental context, however, requires that changes in marine redox structure be tracked by means of geochemical proxies and...

  16. Erosion level of the epithermal Rogovik deposit estimated from geochemical data, northeast Russia (United States)

    Kravtsova, R. G.; Makshakov, A. S.


    The geochemical zoning of the Rogovik epithermal deposit in northeast Russia has been established on the basis of endogenic anomalous geochemical fields (AGCF) of Au-Ag zones, their qualitative and quantitative compositions, and spatial distribution of chemical element indicators of Au-Ag mineralization. The obtained geochemical data (monoelemental AGCF, associations of elements, their composition, contrast, and correlation) allowed us to estimate the erosion level of Au-Ag ore zones. It has been shown that AGCF related to Au-Ag mineralization are distinguished by simple component composition (Au, Ag, Hg, Sb, As, Cu, Pb, Zn) and regular spatial distribution of the elements. It has been established that the least eroded central part of the object is characterized by widespread and the most contrasting Au, Ag, Hg, Sb, and As AGCF closely related to the ore-bearing units of the deposit. The contrast of these fields gradually decreases with depth. Low-contrast Cu, Pb, and Zn AGCF typical of the footwall depth intervals and flanks of Au-Ag zones intervals appear at depth. The northern part of the area is eroded to the deepest level. The contrast of Ag, Hg, Sb, and As geochemical fields abruptly decreases here, and Cu, Pb, and Zn AGCF become widespread with depth. The relatively contrasting fields of anomalous Au concentrations develop here extremely locally and near the surface. It has been concluded that the as yet poorly explored southern part of the Rogovik deposit most likely is promising for further geological exploration and the discovery of new mineralized areas.

  17. Proceedings of the second workshop on hydrologic and geochemical monitoring in the Long Valley Caldera

    Energy Technology Data Exchange (ETDEWEB)

    Sorey, M.L.; Farrar, C.D.; Wollenberg, H.A. (eds.)


    A workshop was held to review the results of hydrologic and geochemical monitoring and scientific drilling in the Long Valley caldera. Such monitoring is being done to detect changes in the hydrothermal system induced by ongoing magmatic and techonic processes. Data from a 2400-ft deep core hole completed in June 1986 were presented at the 1986 workshop and participants discussed the need and rationale for siting locations for future scientific drilling in the caldera.

  18. Geochemical patterns and microbial contribution to iron plaque formation in the rice plant rhizosphere (United States)

    Maisch, Markus; Murata, Chihiro; Unger, Julia; Kappler, Andreas; Schmidt, Caroline


    Rice is the major food source for more than half of the world population and 80 percent of the worldwide rice cultivation is performed on water logged paddy soils. The establishment of reducing conditions in the soil and across the soil-water interface not only stimulates the microbial production and release of the greenhouse gas methane. These settings also create optimal conditions for microbial iron(III) reduction and therefore saturate the system with reduced ferrous iron. Through the reduction and dissolution of ferric minerals that are characterized by their high surface activity, sorbed nutrients and contaminants (e.g. arsenic) will be mobilized and are thus available for uptake by plants. Rice plants have evolved a strategy to release oxygen from their roots in order to prevent iron toxification in highly ferrous environments. The release of oxygen to the reduced paddy soil causes ferric iron plaque formation on the rice roots and finally increases the sorption capacity for toxic metals. To this date the geochemical and microbiological processes that control the formation of iron plaque are not deciphered. It has been hypothesized that iron(II)-oxidizing bacteria play a potential role in the iron(III) mineral formation along the roots. However, not much is known about the actual processes, mineral products, and geochemical gradients that establish within the rhizosphere. In the present study we have developed a growth set-up that allows the co-cultivation of rice plants and iron(II)-oxidizing bacteria, as well as the visual observation and in situ measurement of geochemical parameters. Oxygen and dissolved iron(II) gradients have been measured using microelectrodes and show geochemical hot spots that offer optimal growth conditions for microaerophilic iron(II) oxidizers. First mineral identification attempts of iron plaque have been performed using Mössbauer spectroscopy and microscopy. The obtained results on mineraology and crystallinity have been

  19. Petrological and Geochemical Studies on Granitoids in BibinagarBhongir Area, Nalgonda District, Telangana, India.


    Ch. Ramakrishna; Mallesh, G.; Ch. Ravi; M. Narsimha Reddy


    The Granitoids of the Bibinagar- Bhongir area in the Nalgonda district are purely high potassic calc alkaline and meta aluminous and A-type belongs to Peninsular Gneissic Complex of the Eastern Dharwar Craton. The petrographic study of granitoids indicates that of pure magmatic origin in the form of different magmatic textures viz. perthitic, porphyritic and poiklitic textures. Geochemically the granitoids are rich in K2O & Na2O suggesting source from calc-alkaline magma. The Gran...

  20. Overcoming Challenges to Making Data Re-Usable: The Example of Geochemical Databases (United States)

    Rivera, T. A.; Lehnert, K. A.; Hsu, L.; Johansson, A. K.


    In the early 1990s, the call for systems in which geochemical data could be shared among the research community led to the development of rock-type specific databases, such as PetDB and GEOROC. However, as these and other databases have grown over the last decade, so have the challenges to preserving data integrity, particularly managing of sample metadata. Proper documentation and preservation of metadata are key to qualitative re-use of geochemical data, including the reproduction of the published results. As methodologies advance, and the number of new data-intensive publications increases, the need for documenting and standardizing metadata becomes critical. To date, data managers perform much of the data entry, largely through extracting the geochemical data and associated metadata from publications, as well as performing data quality control and validation. In many cases, especially with legacy data, essential metadata is either missing or becomes a matter of interpretation by the data manager. Following 10 years of data management experience, the Geoinformatics for Geochemistry (GfG) group has recognized four fundamental parameters needed to uphold data reliability: data source, sample information, analytical information, and method-specific information. With the advancement of digital data management and new data policies, the GfG group has begun to solicit the data directly from authors, using templates specifically focused on metadata capture. Once completed, the author uploads the template into the Geochemical Resource Library (GRL), where the data are curated for use by other researchers, educators, and for long-term preservation. From the GRL, a data manager can transfer the data into the appropriate domain database, making them searchable by an expanded audience. Although there are still limitations to the use of the templates, it is an attempt to work more closely with researchers so that the needs for data preservation are communicated and

  1. Natural geochemical risk in the Pollino Massif: a case-study of chromium


    Priscilla Boccia; Salvatore Margiotta


    The geochemical risk linked to heavy metal contamination of soils and waters, commonly associated with anthropogenic causes, may, however, be linked to the presence of rocks and soils that naturally contain these metals. Chromium and nickel are particularly abundant in the ultramafic rocks and ophiolitic and in some crystalline rocks, as well as in soils resulting from these pedogenetic processes (Kierczak et al., 2007). The phenomenon of alteration in charge of such rocks can also determine ...

  2. Geochemical Processes Controlling the Generation and Environmental Impacts of Acid Mine Drainage in Semi Arid Conditions


    Magombedze, Chris


    This study evaluates the geochemical processes that control the geochemistry of acid mine drainage in semi arid conditions. The central objective is to characterise and understand the evolution of acid mine drainage and its potential environmental impacts on the Mazowe River sub-catchment, in north east Zimbabwe. The work is based on a case study at three neighbouring metal sulphide mines, namely Trojan Nickel Mine, Mazowe Gold Mine and Iron Duke Pyrites.The methodology used in this research ...

  3. Proceedings of the second workshop on hydrologic and geochemical monitoring in the Long Valley Caldera

    Energy Technology Data Exchange (ETDEWEB)

    Sorey, M.L.; Farrar, C.D.; Wollenberg, H.A. (eds.)


    A workshop was held to review the results of hydrologic and geochemical monitoring and scientific drilling in the Long Valley caldera. Such monitoring is being done to detect changes in the hydrothermal system induced by ongoing magmatic and techonic processes. Data from a 2400-ft deep core hole completed in June 1986 were presented at the 1986 workshop and participants discussed the need and rationale for siting locations for future scientific drilling in the caldera.

  4. Geochemical and petrographic data for intrusions peripheral to the Big Timber Stock, Crazy Mountains, Montana (United States)

    du Bray, Edward A.; Van Gosen, Bradley S.


    The Paleocene Fort Union Formation hosts a compositionally diverse array of Eocene plugs, dikes, and sills arrayed around the Eocene Big Timber stock in the Crazy Mountains of south-central Montana. The geochemistry and petrography of the sills have not previously been characterized or interpreted. The purpose of this report is (1) to present available geochemical and petrographic data for several dozen samples of these rocks and (2) to provide a basic interpretive synthesis of these data.

  5. Paleoproterozoic snowball Earth: Extreme climatic and geochemical global change and its biological consequences


    Kirschvink, Joseph L.; Gaidos, Eric J.; Bertani, L. Elizabeth; Beukes, Nicholas J.; Gutzmer, Jens; Maepa, Linda N.; Steinberger, Rachel E.


    Geological, geophysical, and geochemical data support a theory that Earth experienced several intervals of intense, global glaciation (“snowball Earth” conditions) during Precambrian time. This snowball model predicts that postglacial, greenhouse-induced warming would lead to the deposition of banded iron formations and cap carbonates. Although global glaciation would have drastically curtailed biological productivity, melting of the oceanic ice would also have induced a cyanobacterial bloom,...

  6. The possible existence of Hs in nature from a geochemical point of view

    CERN Document Server

    Ivanov, A V


    A hypothesis of the existence of a long-lived isotope 271Hs in natural molybdenites and osmirides is considered from a geochemical point of view. It is shown that the presence of Hs in these minerals can be explained only by making an additional ad hoc assumption on the existence of an isobaric pair of 271Bh-271Hs. This assumption could be tested by mass-spectrometric measurements of U, Pb, Kr, Xe, and Zr isotopic shifts.

  7. Geochemical and mineralogical fingerprints to distinguish the exploited ferruginous mineralisations of Grotta della Monaca (Calabria, Italy) (United States)

    Dimuccio, Luca Antonio; Rodrigues, Nelson; Larocca, Felice; Pratas, João; Amado, Ana Margarida; de Carvalho, Luís A. E. Batista


    This study examines the geochemical and mineralogical variations in the ferruginous mineralisations that crop out within Grotta della Monaca, which is considered to be the most striking and best known example of a prehistoric iron mine-cave from the southern Apennines (Calabria, Italy). Previous archaeological research identified three local and distinct ancient exploitation phases of these ferruginous mineralisations: (1) an Upper Palaeolithic phase; (2) a Late Neolithic phase; and (3) a post-Medieval phase. These materials, which have various forms of complex mineralogical admixtures and range in colour from yellow-orange to red and darker brown shades, mainly consist of iron oxides/hydroxides (essentially goethite and lepidocrocite), which are often mixed with subordinate and variable amounts of other matrix components (carbonates, sulphates, arsenates, silicates and organic matter). Such ferruginous mineralisations generally correspond to geochemically heterogeneous massive dyke/vein/mammillary/stratiform facies that are exposed within the local caves along open fractures and inclined bedding planes and that partially cover cave wall niches/notches/pockets and ceiling cupolas/holes. Selected samples/sub-samples are analysed through a multi-technique approach with a handheld portable X-ray Fluorescence, X-ray Diffraction, micro-Raman and Fourier Transform Infrared spectroscope (both conventional and attenuated total reflection), which is combined with subsequent multivariate statistical analysis of the elemental concentration data. The geochemical and mineralogical results are used to individualise similar compositional clusters. As expected, the identified groups, each of which has very specific geochemical-mineralogical "fingerprints" and spatial distributions, enable us to identify the sampled ferruginous mineralisations. These specific mineral resources can be compared to similar raw materials that are found in other neighbouring archaeological sites, with

  8. Geochemical arguments for an Earth-like Moon-forming impactor


    Dauphas, Nicolas; Burkhardt, Christoph; Warren, Paul H.; Fang-Zhen, Teng


    Geochemical evidence suggests that the material accreted by the Earth did not change in nature during Earth's accretion, presumably because the inner protoplanetary disc had uniform isotopic composition similar to enstatite chondrites, aubrites and ungrouped achondrite NWA 5363/5400. Enstatite meteorites and the Earth were derived from the same nebular reservoir but diverged in their chemical evolutions, so no chondrite sample in meteorite collections is representative of the Earth's building...

  9. Connectivity clues from short-term variability in settlement and geochemical tags of mytilid mussels (United States)

    Fodrie, F. Joel; Becker, Bonnie J.; Levin, Lisa A.; Gruenthal, Kristen; McMillan, Pat A.


    The use of geochemical tags in calcified structures of fish and invertebrates is an exciting tool for investigating larval population connectivity. Tag evaluation over relatively short intervals (weeks) may detect environmental and ecological variability at a temporal scale highly relevant to larval transport and settlement. We collected newly settled mussels ( Mytilus californianus and M. galloprovincialis) weekly during winter/spring of 2002 along the coast of San Diego, CA, USA, at sites on the exposed coast (SIO) and in a protected coastal bay (HI), to investigate temporal patterns of geochemical tags in mussel shells. Analyses of post-settlement shell via LA-ICP-MS revealed statistically significant temporal variability for all elements we examined (Mg, Mn, Cu, Sr, Cd, Ba, Pb and U). Despite this, our ability to distinguish multielemental signatures between sites was largely conserved. Throughout our 13-week study, SIO and HI mussels could be chemically distinguished from one another in 78-87% of all cases. Settlement varied between 2 and 27 settlers gram-byssus -1 week -1 at SIO and HI, and both sites were characterized by 2-3 weeks with "high" settlement. Geochemical tags recorded in early larval shell of newly settled mussels differed between "high" and "low" settlement weeks at both sites (MANOVA), driven by Mg and Sr at SIO (p = 0.013) and Sr, Cd, Ba and Pb at HI (p < 0.001). These data imply that shifts in larval sources or transport corridors were responsible for observed settlement variation, rather than increased larval production. In particular, increased settlement at HI was observed concurrent with the appearance of geochemical tags (e.g., elevated Cd), suggesting that those larvae were retained in upwelled water near the mouth of the bay. Such shifts may reflect short-term changes in connectivity among sites due to altered transport corridors, and influence the demography of local populations.

  10. Geochemical study of coral skeletons from the Puerto Morelos Reef, southeastern Mexico (United States)

    Kasper-Zubillaga, Juan J.; Armstrong-Altrin, John S.; Rosales-Hoz, Leticia


    Geochemical analyses in coral skeletons have been used as a proxy of marine environmental conditions and to understand the mechanisms of adsorption of chemical elements into the coral skeletons and growth forms. However, little attention has been given to show the possible differences in the growth rates of corals based upon major, trace, rare earth element and microprobe analyses to examine the physical-chemical conditions influencing those differences. Our goal is to show how branch and fan corals incorporate elements into their skeletons comparing them with their coral growth rates. We determine the development of the skeletons of two branching (Acropora palmata, Acropora cervicornis) and one fan shaped (Gorgonia ventalina) colonies in the Puerto Morelos Reef, southeastern Mexico based upon geochemical data and the influence of terrigenous input into the species. Mg and Sr concentrations were the most statistically significant elements among the species studied suggesting that Mg concentration in Gorgonia ventalina is probably not linked to its growth rate. Mn content in the sea water is adsorbed by the three corals during past growth rates during high rainfall events. Sr concentration may be associated with the growth rate of Acropora palmata. Little differences in the growth rate in Acropora palmata may be associated with low rates of calcitization, negligible changes in the Sr concentration and little influence of temperature and water depth in its growth. Trace elements like Cr, Co, Ni and V adsorbed by the corals are influenced by natural concentration of these elements in the sea-water. Rare earth elements in the corals studied suggests abundant inorganic ions CO32- with variable pH in modern shallow well-oxygenated sea water. Lack of terrigenous input seawards is supported by geochemical, geomorphological and biological evidences. This study is an example of how geochemical data are useful to observe the differences in environmental conditions related to

  11. Geochemical variation of groundwater in the Abruzzi region: earthquakes related signals? (United States)

    Cardellini, C.; Chiodini, G.; Caliro, S.; Frondini, F.; Avino, R.; Minopoli, C.; Morgantini, N.


    The presence of a deep and inorganic source of CO2 has been recently recognized in Italy on the basis of the deeply derived carbon dissolved in the groundwater. In particular, the regional map of CO2 Earth degassing shows that two large degassing structures affect the Tyrrhenian side of the Italian peninsula. The northern degassing structure (TRDS, Tuscan Roman degassing structure) includes Tuscany, Latium and part of Umbria regions (~30000 km2) and releases > 6.1 Mt/y of deeply derived CO2. The southern degassing structure (CDS, Campanian degassing structure) affects the Campania region (~10000 km2) and releases > 3.1 Mt/y of deeply derived CO2. The total CO2 released by TRDS and CDS (> 9.2 Mt/y) is globally significant, being ~10% of the estimated present-day total CO2 discharge from sub aerial volcanoes of the Earth. The comparison between the map of CO2 Earth degassing and of the location of the Italian earthquakes highlights that the anomalous CO2 flux suddenly disappears in the Apennine in correspondence of a narrow band where most of the seismicity concentrates. A previous conceptual model proposed that in this area, at the eastern borders of TRDS and CDS plumes, the CO2 from the mantle wedge intrudes the crust and accumulate in structural traps generating over-pressurized reservoirs. These CO2 over-pressurized levels can play a major role in triggering the Apennine earthquakes, by reducing fault strength and potentially controlling the nucleation, arrest, and recurrence of both micro and major (M>5) earthquakes. The 2009 Abruzzo earthquakes, like previous seismic crises in the Northern Apennine, occurred at the border of the TRDS, suggesting also in this case a possible role played by deeply derived fluids in the earthquake generation. In order to investigate this process, detailed hydro-geochemical campaigns started immediately after the main shock of the 6th of April 2009. The surveys include the main springs of the area which were previously studied in

  12. Study on mineralization at Jian copper deposit, Fars province, using petrographical and geochemical data

    Directory of Open Access Journals (Sweden)

    Mohamad Ali Rajabzade


    Full Text Available Jian Cu deposit is hosted by Surian volcano-sedimentary complex of Permo-Triassic age on the eastern edge of the Sanandaj-Sirjan metamorphic zone at a distance of 195 km from Shiraz, southwestern Iran. The complex consists mainly of metabasalt, chlorite-quartz schist, chlorite-muscovite schist, mica schist and graphite schist. Pyrite is the most important sulfide and chalcopyrite is the major Cu-bearing mineral occurring as disseminated grains and veinlets in host chlorite-quartz schist and chlorite-muscovite schist. Chondrite-normalized REE pattern of metabasalt with La/LuN=2/9 indicates mantle tholeiitic basalt as the source of metamorphosed igneous rocks. Geochemical data on the metabasalts, especially the content of immobile elements (e.g., Ti and High Field Strength Elements (HFSE (e.g., Zr، Nb and Y, show low degree of partial melting for parental magma with E-MORB affinity. Chloritic, silicification and minor sericitic assemblages are the main alteration types associated with the Jian Cu deposit. The Y/Ho ratio of Cu ores varies from 29.9 to 32.5, indicating the important role of sea water in the mineralizing system. Petrographical and geochemical data indicate that the Jian Cu deposit was formed as volcano-sedimentary hosted massive sulfide. The Ishikawa alteration index (AI in association with chlorite-carbonate-pyrite index (CCP is useful for the geochemical exploration of Cu deposits in the study area.

  13. Application of REE geochemical signatures for Mesozoic sediment provenance to the Gettysburg Basin, Pennsylvania (United States)

    Blake, Johanna M.; Peters, Stephen C.; Johannesson, Karen H.


    Rift basins adjacent to accreted terranes provide accommodation space for sediments eroded from these terranes. Despite similar depositional environments and geologic age, rocks of the Triassic Gettysburg Basin have approximately half the arsenic concentrations of the adjacent Newark Basin. Quartz-feldspar-lithics (QFL) diagrams and rare earth element (REE) geochemical signatures can inform sediment provenance. Here we investigate REE geochemical signatures of the sedimentary rocks in the Triassic Gettysburg rift basin, with the goal of distinguishing the main sources of siliciclastic sediment among the Appalachian foreland in the rift footwall from Piedmont arc and Iapetan continental margin rocks exposed in the hanging wall and ultimately understanding the geochemical cycling of arsenic to the Gettysburg Basin. Shale-normalized REE spider diagrams and Mann-Whitney tests on trace element ratios suggest that the Gettysburg Basin samples show patterns that most closely resemble those of the Iapetus Continental Slope Rise Iapetus Rift Volcanic, and Accretionary Complex deposits. Mann-Whitney Rank Sum analysis suggest that the Iapetus Continental Slope Rise terrane is the main source of sediments to the basin, which confirms results from prior QFL analysis and shows the utility of REE fingerprinting in provenance analysis. The main sources of sediment have smaller minimum and maximum arsenic concentrations than other terranes and the Newark Basin sediments, additionally suggesting the source of arsenic to the Gettysburg Basin is based upon specific terranes.

  14. Factors of the accumulation of heavy metals and metalloids at geochemical barriers in urban soils (United States)

    Kosheleva, N. E.; Kasimov, N. S.; Vlasov, D. V.


    The bulk contents and concentrations of mobile (extracted by an ammonium acetate buffer with EDTA) Cd, Pb, Sb, As, Bi, Zn, and Cu were determined in the surface horizons of urban soils in the Eastern administrative okrug of Moscow. The regression analysis showed that the accumulation of these metals and metalloids in the soils is controlled by the physicochemical soil properties and by number of anthropogenic factors and landscape conditions (geochemical position, type of loose deposits, character of land use, dust load, vehicle emissions, building pattern, percent of green areas, and the extent of sealed soils). The precipitation of studied elements on the geochemical barriers had the following regularities: Cd, Cu, and Zn accumulated on the alkaline barriers; Bi, Sb, As, Cu, Pb, and Zn, on chemisorption barriers; Sb, As, and Pb, on organomineral barriers; and Cd and Cu, on the sorption-sedimentation barriers. Technogenic transformation of the physicochemical properties of urban soils resulted in the increase of the mean bulk contents of heavy metals and metalloids by 33-99%; the portion of elements fixed on the geochemical barriers increased by 26-50%.

  15. Lead and zinc geochemical behavior based on geological characteristics in Parkam Porphyry Copper System, Kerman, Iran

    Institute of Scientific and Technical Information of China (English)

    Seyyed; Saeed; Ghannadpour; Ardeshir; Hezarkhani


    Parkam(Sarah) porphyry system is located on the metallogenic belt of Kerman, Iran. Due to existence of some copper-rich resources in this region, finding out the exact statistical characteristics such as distribution of data population, mean, variance and data population behavior of elements like Cu, Mo, Pb and Zn is necessary for interpreting their geological behavior. For this reason, precise calculation of statistical characteristics of Pb and Zn grade datasets was performed and results were interpreted geologically. The natures of Pb and Zn distributions were initially identified and their distributions were normalized through statistical treatment. Subsequently, the variograms were calculated for each exploration borehole and show that both Pb and Zn geochemical variates are spatially correlated. According to the similarity of the behavior of Pb and Zn in these calculations, it is decided to measure their exact behavior applying K-means clustering method. K-means clustering results show that the Zn grade varies linearly relative to that of Pb values and their behavior is similar. Based on the geochemical behavior similarity of Pb and Zn, throughout the pervasive secondary hydrothermal activity, they are remobilized in the similar manner, from the deep to the shallow levels of the mineralization zones. However, statistical analysis suggests that hydrothermal activity associated with secondary waters in Parkam is effective in remobilizing and enriching both Pb and Zn since they have similar geochemical characteristics. However, the process does not result in generation of economic concentrations.

  16. Investigation of Hydrologic and Geochemical Properties of an Unsaturated Waste Rock Pile at Key Lake, Saskatchewan (United States)

    Stockwell, J.; Smith, L.; Beckie, R.


    Waste rock is any rock that must be removed to gain access to the ore at a mine. Waste rock piles at mine sites often rest above the water table, which exposes the rock to oxygen, and promotes the oxidation of sulfide minerals releasing sulfuric acid, metals and heat. Water flow through unsaturated waste rock and its role in geochemical processes is not well understood. The objective of this work was to identify spatial relationships between hydrologic and geochemical properties of waste rock. A 12-meter high waste rock pile was deconstructed and sampled during the summer of 2000. Approximately 175 samples were collected to assess the physical properties of matric potential, volumetric water content, and grain-size distribution and the geochemical properties of temperature, paste pH, pore-water chemistry, mineralogy, and bulk rock chemistry. In addition, we characterized weathering using selective extractions that target the weathering products that contain sulfur and iron. We discuss the influence of fluid flow paths, gain-size distribution, mineralogy and sample volume on the characterization of waste rock weathering.

  17. Geochemical characteristics of Guizhou Permian coal measure strata and analysis of the control factors

    Institute of Scientific and Technical Information of China (English)

    YANG Rui-dong; LIU Ling; WEI Huai-rui; CUI Yu-chao; CHENG Wei


    Based on element geochemical studies of the main Permian exploitable coal measure strata in Western Guizhou, the element geochemical distribution characteristics of the main exploitable coal measures were revealed in the regions of Dafang,Qianxi, Weining, Hezhang, Zhijin, etc., of Guizhou Province, and the results show that their element contents are mainly affected by terrestrial material supply. Coal measures formed in the delta plain environment where sufficient terrestrial materials are supplied contain relatively abundant trace elements and rare-earth elements, whereas those formed in the tidal-flat environment influenced greatly by seawater have relatively low contents of trace elements and rare-earth elements, mainly controlled by the geological fact that basalts the parent rocks from source regions contain high trace elements and rare-earth elements. In addition, coal measures affected by later hydrothermal activities and fault tectonics contain a large amount of harmful elements. According to the rules of distribution of elements in coal measures, a new idea was put forward to classify coal-forming environments by using the geochemical composition characteristics, which is of great significance in dissolving the problem of whether coal measures were formed either in delta environments or in tidal-flat environments in Western Guizhou. At the same time, the rules of distribution of elements in the main exploitable coal measures in Western Guizhou were fully understood, which is of direct significance in utilizing coal resources on the basis of classification of coals, as well as in developing the coal chemical industry.

  18. Geochemical characteristics of the Permian sedimentary rocks from Qiangtang Basin: Constraints for paleoenvironment and paleoclimate

    Directory of Open Access Journals (Sweden)

    Junjie Hu


    Full Text Available Qiangtang Basin is expected to become important strategic petroleum exploitation area in China. However, little research has been done on the Permian strata in this area. This paper presents Lower Permian Zhanjin Formation geochemical data from the Jiaomuri area, reconstructing the paleo-depositional environment and providing information for further petroleum exploration. The geochemical characteristics of 19 samples were investigated. These geochemical samples show a developed mud flat characteristic with light rich clay content. The geological data were used to constrain the paleoredox environment, which proved that these sediments were deposited mainly beneath a slightly oxic water column with relatively low paleoproductivity as evidenced by the P/Ti (mean of 0.07 and Ba/Al (mean of 20.5. Palaeoclimate indexes such as the C-value (0.24-1.75 and Sr/Cu (1.28-11.58 reveal a humid climatic condition during Zhanjin Formation sediment deposition. The ω(LaN/ω(YbN ratio values indicate a fast sedimentary rate during the deposition period.

  19. Co-transport of metals and organic compounds in geochemical, biochemical and environmental processes

    Energy Technology Data Exchange (ETDEWEB)

    Shock, E.L. [GEOPIG, St. Louis, Washington Univ., MO (United States). Dept. of Earth and Planetary Sciences


    If the environment is defined as consisting of the interdependent processes that enable life to persist, then environmental science begins where geology and biology overlap. It follows that the environmental chemistry emerges from the confluence of geochemistry and biochemistry. With increasing evidence that the biosphere extends well into what has traditionally been considered the sterile geosphere, perhaps even to thousands of meters of the crust (Ghiorse and Wilson, 1988; Pedersen and Ekendahl, 1990; Stevens and McKinley, 1995; Boone et al., 1995), many crustal geochemical processes are being re-evaluated in terms of their potential for supporting life, and microorganisms are increasingly invoked to explain the rates and mechanisms of reactions in geochemical processes (Banfield and Hamers, 1997; Barker et al.,1997; Bazylinski and Moskowitz, 1997; Fortin et al., 1997; Little et al., 1997; McCollom and Shock, 1997; Nordstrom and Southam, 1997; Tebo et al., 1997). Elemental mobility from the geosphere to the hydrosphere, biosphere and atmosphere occurs in surface reactions that are often mediated by microorganisms that actively uptake metals and other nutrients from their surrounding geochemical environments.

  20. High-Resolution Geochemical Significance of Lowest Triassic at Majiashan Section, Chaohu, Anhui Province, China

    Institute of Scientific and Technical Information of China (English)


    The Permian-Triassic boundary (PTB) and the lowest Triassic in the Yangtze region are considered to be the sediments of dysaeroxic and even anoxic environments, due to the dark thin-bedded fine deposits, the highly developed parallel beddings with pyrites, the suppression of bio-disturbance, and the monotonoas fossils. However, the trace fossils there show a rather weak effect of the anoxic event. Meanwhile, the high-resolution geochemical data are analyzed with 2-cm interval in the PTB and the lowest Triassic at the Majiashan Section, Chaohu, Anhui Province. The results show that the water depth of Chaohu region in the earliest Triassic was shallow, which might be a feature of the neritic environment. The high-resolution geochemical proxies for anoxia have some contrary results. The geochemical data often indicate the dysaeroxic and even anoxic environments during that time, whereas other proxies (such as w(V)/w(Cr), w(Ni)/w(Co)) denote that they are normal marine sediments.

  1. Geochemical effects on the behavior of LLW radionuclides in soil/groundwater environments

    Energy Technology Data Exchange (ETDEWEB)

    Krupka, K.M.; Sterne, R.J. [Pacific Northwest Lab., Richland, WA (United States)


    Assessing the migration potential of radionuclides leached from low-level radioactive waste (LLW) and decommissioning sites necessitates information on the effects of sorption and precipitation on the concentrations of dissolved radionuclides. Such an assessment requires that the geochemical processes of aqueous speciation, complexation, oxidation/reduction, and ion exchange be taken into account. The Pacific Northwest National Laboratory (PNNL) is providing technical support to the U.S. Nuclear Regulatory Commission (NRC) for defining the solubility and sorption behavior of radionuclides in soil/ground-water environments associated with engineered cementitious LLW disposal systems and decommissioning sites. Geochemical modeling is being used to predict solubility limits for radionuclides under geochemical conditions associated with these environments. The solubility limits are being used as maximum concentration limits in performance assessment calculations describing the release of contaminants from waste sources. Available data were compiled regarding the sorption potential of radionuclides onto {open_quotes}fresh{close_quotes} cement/concrete where the expected pH of the cement pore waters will equal to or exceed 10. Based on information gleaned from the literature, a list of preferred minimum distribution coefficients (Kd`s) was developed for these radionuclides. The K{sub d} values are specific to the chemical environments associated with the evolution of the compositions of cement/concrete pore waters.

  2. Multiphase fluid flow and subsequent geochemical transport invariably saturated fractured rocks: 1. Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tianfu; Pruess, Karsten


    Reactive fluid flow and geochemical transport in unsaturated fractured rocks has received increasing attention for studies of contaminant transport, groundwater quality, waste disposal, acid mine drainage remediation, mineral deposits, sedimentary diagenesis, and fluid-rock interactions in hydrothermal systems. This paper presents methods for modeling geochemical systems that emphasize: (1) involvement of the gas phase in addition to liquid and solid phases in fluid flow, mass transport and chemical reactions, (2) treatment of physically and chemically heterogeneous and fractured rocks, (3) the effect of heat on fluid flow and reaction properties and processes, and (4) the kinetics of fluid-rock interaction. The physical and chemical process model is embodied in a system of partial differential equations for flow and transport, coupled to algebraic equations and ordinary differential equations for chemical interactions. For numerical solution, the continuum equations are discretized in space and time. Space discretization is based on a flexible integral finite difference approach that can use irregular gridding to model geologic structure; time is discretized fully implicitly as a first-order finite difference. Heterogeneous and fractured media are treated with a general multiple interacting continua method that includes double-porosity, dual-permeability, and multi-region models as special cases. A sequential iteration approach is used to treat the coupling between fluid flow and mass transport on the one hand, chemical reactions on the other. Applications of the methods developed here to variably saturated geochemical systems are presented in a companion paper (part 2, this issue).

  3. Salinity contamination response to changes in irrigation management. Application of geochemical codes

    Directory of Open Access Journals (Sweden)

    Iker Garcia-Garizabal


    Full Text Available Salinity contamination caused by irrigation has been widely studied but the analysis of geochemical processes regarding agronomic variables has not adequately been considered yet. The research presented here analyzes the influence of changes in irrigation management on salinity contamination, through the use of geochemical modeling techniques, in an agricultural basin during the hydrological year of 2001 and within the period 2005-2008. The results indicate that the changes implemented in irrigation management reduced the masses of salts exported in 72%, although water salinity increased by 25% (this salinity level does not restrict its use for irrigation. The different ionic ratios in drainage water, the results of the salinity balances, and the results of geochemical calculations (mass balances and speciation-solubility indicate, mainly, precipitation of calcite, dissolution of gypsum and halite and cation exchange. The salt contamination index decreased from approximately 70% to levels close to those presented in modern irrigation areas, indicating that the changes in irrigation management were effective. Petrocalcic genesis and punctual sodification of soils can constitute an agroenvironmental problem that requires adequate management of irrigation and drainage considering future modernization of irrigation areas.

  4. Geochemical Characteristics and Origin of Tar Mats from the Yaha Field in Tarim Basin,China

    Institute of Scientific and Technical Information of China (English)

    张敏; 张俊; 等


    Tar mats were firstly discovered and determined accurately in terrestrial oil and gas reservoirs associated with Lower Tertiary sandstone reservoirs in the Yaha field of the Tarim Basin,China,by thin-layer chromatography-flame ionization detector(TLC-FID)and Rock-Eval analysis.The relative content of asphaltene in gross composition of tar mat extracts accounts for more than 30%,that in the corresponding oil leg less than 20%.In the geochemical description profile of oil gas reservoirs,drastic changes in asphaltene contents between tar mats and oil legs could be discovered.This in an important marker to determine tar mats.Distribution characteristics of saturated and aromaic hydrocarbons from reservoir core extracts and crude oils in the Yaha oil and gas reservoirs in the Tarim Basin are described systematically in this paper,and the results show there are similarities among n-alkane distribution characteristics,biomarker distribution characteristics and their combined characteristics of saturated hydrocarbons,and the geochemical characteristics of aromatic hydrocarbons for tar mats.oil leg,asphaltic sand and crude oil.These characteristics suggest the hydrocarbons in these samples were originated from the common source rocks.However,the geochemical characteristics of tar mats reveales that the mechanism of formation of tar mats is the precipitation of asphaltene from crude oils in petroleum reservoirs caused by increased dissolved gas in oil legs(gas injection).

  5. Paleoenvironmental reconstruction of marginal marine environments from combined paleoecological and geochemical analyses on ostracods (United States)

    Anadón, P.; Gliozzi, E.; Mazzini, I.

    Marginal marine environments are complex systems, which show physico-chemical instability due to seawater/fresh water interactions. During the Quaternary these features have been more complicated by the global climatic and sea level variations. Consequently, the use of ostracod shell chemistry (trace elements, δ13C, δ18O and 87Sr/86Sr) to decode the paleohydrochemical characters often is not enough to understand the paleoenvironmental changes. But, if geochemistry is coupled with the classic taxonomical/paleoecological analyses, it may provide a more unambiguous reconstruction. Combined geochemical and paleoecological analyses on ostracods were applied to two boreholes drilled in Quaternary sequences in central Italy. At Migliara (Latium), the inferred salinity deduced from ecology and geochemical data on Cyprideis shells suggests a simple mixing between marine and fresh water, mainly caused by sea-level oscillations. The lack of correlation between ostracod ecology and geochemical data in the Albinia core (Tuscany) can be explained by the mixing of waters from at least three different sources

  6. Genesis and organic geochemical characteristics of the carbonaceous rock stratabound gold deposits, South China

    Institute of Scientific and Technical Information of China (English)


    The organic matter of three different chronological major carbonaceous rock gold-bearing formations of South China (Middle Proterozoic Shangqiaoshan group of northeastern Jiangxi, Lower Cambrian Shuikou group of northern Guangxi and Devonian Shetianqiao group of eastern Hunan) and related carbonaceous stratabound gold deposits such as Jinshan, Longshui and Shixia deposits, respectively, has been characterized by organic geochemical techniques. These organic geochemical results show that the average total organic carbon (TOC) content of the three chronological carbonaceous rock gold-bearing formations of South China ranges from 0.15% to 1.56%. The thermal maturity of the organic matter of host rocks in the three gold-bearing formations is high. The micro-component of the organic matter of the host rocks consists primarily of solid bitumen and graphite. The organic carbon and gold of the host rocks appear to syndeposit in situ during the formation of the gold-bearing formations. The organic carbon played a certain role in controlling the geochemical environment of the gold-bearing formations. The metallogenetic mechanism of the carbonaceous rock stratabound gold deposits of South China is closely associated in genesis with the sedimentation, diagenesis and thermal evolution history of the organic matter of host rocks in the gold-bearing formations.

  7. Mineralogical and Geochemical Trends in a Fluviolacustrine Sequence in Gale Crater, Mars (United States)

    Rampe, E.; Ming, D.; Morris, R.; Blake, D.; Vaniman, D.; Bristow, T.; Chipera, S.; Yen, A.; Grotzinger, J.; DesMarais, D.


    The Mars Science Laboratory rover, Curiosity, landed at Gale crater in August 2012 and has been investigating a sequence of dominantly fluviolacustrine sediments deposited 3.6-3.2 billion years ago. Curiosity collects quantitative mineralogical data with the CheMin XRD/XRF instrument and quantitative chemical data with the APXS and ChemCam instruments. These datasets show stratigraphic mineralogical and geochemical variability that suggest a complex aqueous history. The Murray Formation, primarily composed of fine-laminated mudstone, has been studied in detail since the arrival at the Pahrump Hills in September 2014. CheMin data from four samples show variable amounts of iron oxides, phyllosilicates, sulfates, amorphous and crystalline silica, and mafic silicate minerals. Geochemical data throughout the section show that there is significant variability in Zn, Ni, and Mn concentrations. Mineralogical and geochemical trends with stratigraphy suggest one of possibly several aqueous episodes involved alteration in an open system under acidic pH, though other working hypotheses may explain these and other trends. Data from the Murray Formation contrast with those collected from the Sheepbed mudstone located approximately 60 meters below the base of the Murray Formation, which showed evidence for diagenesis in a closed system at circumneutral pH. Ca-sulfates filled late-stage veins in both mudstones.

  8. [Determination of high content of tin in geochemical samples by solid emission spectrometry]. (United States)

    Yao, Jian-Zhen; Hao, Zhi-Hong; Tang, Rui-Ling; Li, Xiao-Jing; Li, Wen-Ge; Zhang, Qin


    A method for the determination of high content of tin in geochemical samples by solid emission spectrometry was presented. The dedicated high content tin spectrum standard series was developed. K2S2O7, NaF, Al2O3 and carbon powder were used as buffers and Ge was used as internal standard, and the ratio of sample/matrix/buffer is 1 : 1 : 2. A weak sensitive line (Sn 242. 170 0 nm) was used as the analytical line. The technologies of vertical electrodes, AC arc overlap spectrograph, interception of the exposure, quantitative computer translation spectrum and background correction were used. The determination range is 100-22 350 microg x g(-1), the detection limit is 16.64 microg x g(-1), and the precision is (RSD, n = 12) 4.11%-6.46%. The accuracy of the method has been verified by determination of high content of tin in national geochemical standard samples and the results are in agreement with certified value. The method can be used for measurement directly without dilution of high content of tin in geochemical samples, and it greatly improved the detection upper limit for the determination of tin with solid emission spectroscopy and has certain practical value.

  9. Geochemical markers and polycyclic aromatic hydrocarbons in solvent extracts from diesel engine particulate matter. (United States)

    Fabiańska, Monika; Kozielska, Barbara; Bielaczyc, Piotr; Woodburn, Joseph; Konieczyński, Jan


    Exhaust particulate from compression ignition (CI) engines running on engine and chassis dynamometers was studied. Particulate dichloromethane extracts were qualitatively and quantitatively analyzed for polycyclic aromatic hydrocarbons (PAHs) and biomarkers by gas chromatography with flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). PAH group profiles were made and the PAH group shares according to the number of rings (2 or 3; 4; 5 or more) as well as diagnostic indices were calculated. Values of geochemical ratios of selected biomarkers and alkyl aromatic hydrocarbons were compared with literature values. A geochemical interpretation was carried out using these values and biomarker and alkyl aromatic hydrocarbon distributions. It has been shown that geochemical features are unequivocally connected to the emission of fossil fuels and biofuels burned in CI engines. The effect of the exothermic combustion process is limited to low-molecular-weight compounds, which shows that the applied methodology permits source identification of PAHs coexisting in the particulate emitted.

  10. Instrumenting caves to collect hydrologic and geochemical data: case study from James Cave, Virginia (United States)

    Schreiber, Madeline E.; Schwartz, Benjamin F.; Orndorff, William; Doctor, Daniel H.; Eagle, Sarah D.; Gerst, Jonathan D.


    Karst aquifers are productive groundwater systems, supplying approximately 25 % of the world’s drinking water. Sustainable use of this critical water supply requires information about rates of recharge to karst aquifers. The overall goal of this project is to collect long-term, high-resolution hydrologic and geochemical datasets at James Cave, Virginia, to evaluate the quantity and quality of recharge to the karst system. To achieve this goal, the cave has been instrumented for continuous (10-min interval) measurement of the (1) temperature and rate of precipitation; (2) temperature, specific conductance, and rate of epikarst dripwater; (3) temperature of the cave air; and (4) temperature, conductivity, and discharge of the cave stream. Instrumentation has also been installed to collect both composite and grab samples of precipitation, soil water, the cave stream, and dripwater for geochemical analysis. This chapter provides detailed information about the instrumentation, data processing, and data management; shows examples of collected datasets; and discusses recommendations for other researchers interested in hydrologic and geochemical monitoring of cave systems. Results from the research, briefly described here and discussed in more detail in other publications, document a strong seasonality of the start of the recharge season, the extent of the recharge season, and the geochemistry of recharge.

  11. [Study on the Geochemical Anomalies Identification of REE Based on HJ-1A-HSI]. (United States)

    Chen, Yong-gan; Wang, Mei-juan; Li, Peng


    The characteristic spectral bands of REE do not vary with the occurrence state, cannot be used to identify mineral species, but can prove the existence of its own. Here we report the spectrum characteristics of REE and their compounds by remote sensing wave band from visible light-near infrared, with the quantitative relationship between the contents of REE and absorption index of characteristic spectral bands. The experimental study was carried out in Bayan Obo area, Inner Mongolia. Spectrums and Nd contents of typical rock and ore samples were gathered and analyzed. There is positive correlation between the Nd content, the absorption depth and absorption index of different spectrum characteristics (correlation coefficient > 0.778). Moreover, the correlation between absorption index of 726-772 nm band and Nd content is the best, at 0. 937. As mentioned above, the quantitative model and the inversion information remote sensing geochemical anomaly of Nd were built by the band of HJ-1A-HIS hyperspectral remote sensing data. Our results consistent with 1:200,000 stream sediment geochemical anomalies of Nd. The model provides a new means for rapid extract regional geochemical anomalies of REE.

  12. Edge Effect Correction in the S-A Method for Geochemical Anomaly Separation

    Institute of Scientific and Technical Information of China (English)

    Ge Yong; Cheng Qiuming; Zhang Shenyuan


    Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and holes (with missing data) often causes frequency distribution distortion in the frequency domain. For example, bright strips are commonly seen in frequency distribution when using a Fourier transform. Such edge effect distortion may affect information extraction results; sometimes severely, depending on the edge abruptness of the image. Traditionally, edge effects are reduced by smoothing the image boundary prior to applying a Fourier transform. Zero-padding is one of the most commonly used smoothing methods. This simple method can reduce the edge effect to some degree but still distorts the image in some cases. Moreover, due to the complexity of geoscience images, which can include irregular shapes and holes with missing data, zero-padding does not always give satisfactory results. This paper proposes the use of decay functions to handle edge effects when extracting information from geoscience images. As an application, this method has been used in a newly developed multifractal method (S-A) for separating geochemical anomalies from background patterns. A geochemical dataset chosen from a mineral district in Nova Scotia, Canada was used to validate the method.

  13. Experimental study on geochemical characteristic of methane hydrate formed in porous media

    Institute of Scientific and Technical Information of China (English)

    Qiang Chen; Changling Liu; Yuguang Ye


    The natural occurrence of methane hydrates in marine sediments has been intensively studied over the past decades, and geochemical charac-teristic of hydrate is one of the most attractive research fields. In this paper, we discussed the geochemical anomaly during hydrate formation in porous media. By doing so, we also investigated the temperature influence on hydrate formation under isobaric condition. It turns out that sub-cooling is an important factor to dominate hydrate formation. Larger subcooling provides more powerful driving force for hydrate formation. During the geochemical anomaly research, six kinds of ions and the total dissolved salt (TDS) were measured before and after the experiment in different porous media. The result is that all kinds of ionic concentration increased after hydrate formation which can be defined as salting out effect mainly affected by gas consumption. But the variation ratio of different ions is not equal. Ca2+ seems to be the most significantly influenced one, and its variation ratio is up to 80%. Finally, we theoretically made a model to calculate the TDS variation, the result is in good accordance with measured one, especially when gas consumption is large.

  14. Multivariate analysis of ATR-FTIR spectra for assessment of oil shale organic geochemical properties (United States)

    Washburn, Kathryn E.; Birdwell, Justin E.


    In this study, attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FTIR) was coupled with partial least squares regression (PLSR) analysis to relate spectral data to parameters from total organic carbon (TOC) analysis and programmed pyrolysis to assess the feasibility of developing predictive models to estimate important organic geochemical parameters. The advantage of ATR-FTIR over traditional analytical methods is that source rocks can be analyzed in the laboratory or field in seconds, facilitating more rapid and thorough screening than would be possible using other tools. ATR-FTIR spectra, TOC concentrations and Rock–Eval parameters were measured for a set of oil shales from deposits around the world and several pyrolyzed oil shale samples. PLSR models were developed to predict the measured geochemical parameters from infrared spectra. Application of the resulting models to a set of test spectra excluded from the training set generated accurate predictions of TOC and most Rock–Eval parameters. The critical region of the infrared spectrum for assessing S1, S2, Hydrogen Index and TOC consisted of aliphatic organic moieties (2800–3000 cm−1) and the models generated a better correlation with measured values of TOC and S2 than did integrated aliphatic peak areas. The results suggest that combining ATR-FTIR with PLSR is a reliable approach for estimating useful geochemical parameters of oil shales that is faster and requires less sample preparation than current screening methods.

  15. The Geochemical Features and Evolution of Laterite in the Karst Areas of Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    朱立军; 林进也


    Guizhou is one of the dominating karst regions,where laterite is widespread,in China.Seventy-two laterite samples were taken from twelve laterite sections in the karst areas of Guizhou Province,which are possessed of typical subtropical karst geomphological and ecological environmental features and have evolved completely from dolostones and limestones.In terms of the major,trace and REE deta for thd samples this paper discusses the geochemical characteristics of laterite in the karst areas with an attempt to disclose the geochemical process and evolutionary rule of laterite formation.There have been involved three important pedogenetic geochemical precesses in the formation of laterite in the karst areas:(1)enrichment of silicon and aluminum and depletion of calcium and magnesium;(2)enrichment of iron and manganese;and(3) enrichment of aluminum and depletion of silicon.During the formation and evolution of laterite,obvious enrichment and differentiation of trace elements such as Cu,Pb,Zn,Ni,Co,Cr,Pb,F,Cl,and As can be observed,but for the rare-earth elements,their enrichment is remarkable against a weak differentiation.The REE distribution patterns in the laterite are similar to those of its parental carbonate rocks.

  16. Geochemical properties and nuclear chemical characteristics of Oklo natural fission reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hidaka, Hiroshi [Hiroshima Univ., Higashi-Hiroshima (Japan). Faculty of Science


    There are six uranium deposits in the Gabonese Republic in the cnetral Africa. `Fission reactor zone`, the fission chain reactions generated about 200 billion years ago, was existed in a part of them. CEA begun geochemical researches of Oklo deposits etc. in 1991. The geochemical and nuclear chemical properties of Oklo were reviewed from the results of researches. Oklo deposits is consisted of main five sedimentary faces such as sandstone (FA), Black Shale formation (FB), mudstone (FC), tuff (FD) and volcaniclastic sandstone (FE) from the bottom on the base rock of granite in the Precambrian era. Uranium is enriched in the upper part of FA layer and the under part of FB layer. {sup 235}U/{sup 238}U, U content, fission proportion, duration time, neutron fluence, temperature, restitution factor of {sup 235}U and epithermal index ({gamma}) were investigated and compared. The geochemical properties of Oklo are as followed: large enrich of uranium, the abundance ratio of {sup 235}U as same as that of enriched uranium, interaction of natural water and small rear earth elements. These factors made casually Oklo fission reactor. (S.Y.)

  17. In Situ Rates of Sulfate Reduction in Response to Geochemical Perturbations (United States)

    Kneeshaw, T.A.; McGuire, J.T.; Cozzarelli, I.M.; Smith, E.W.


    Rates of in situ microbial sulfate reduction in response to geochemical perturbations were determined using Native Organism Geochemical Experimentation Enclosures (NOGEEs), a new in situ technique developed to facilitate evaluation of controls on microbial reaction rates. NOGEEs function by first trapping a native microbial community in situ and then subjecting it to geochemical perturbations through the introduction of various test solutions. On three occasions, NOGEEs were used at the Norman Landfill research site in Norman, Oklahoma, to evaluate sulfate-reduction rates in wetland sediments impacted by landfill leachate. The initial experiment, in May 2007, consisted of five introductions of a sulfate test solution over 11 d. Each test stimulated sulfate reduction with rates increasing until an apparent maximum was achieved. Two subsequent experiments, conducted in October 2007 and February 2008, evaluated the effects of concentration on sulfate-reduction rates. Results from these experiments showed that faster sulfate-reduction rates were associated with increased sulfate concentrations. Understanding variability in sulfate-reduction rates in response to perturbations may be an important factor in predicting rates of natural attenuation and bioremediation of contaminants in systems not at biogeochemical equilibrium. Copyright ?? 2011 The Author(s). Journal compilation ?? 2011 National Ground Water Association.

  18. Geochemical evolution of the near field of a KBS-3 repository

    Energy Technology Data Exchange (ETDEWEB)

    Arcos, David; Grandia, Fidel; Domenech, Cristina [Enviros Spain S.L., Barcelona (Spain)


    The Swedish concept developed by SKB for deep radioactive waste disposal, envisages an engineered multi-barrier system surrounding the nuclear waste (near field). In the present study we developed a numerical model to assess the geochemical evolution of the near field in the frame of the SKB's safety assessment SR-Can. These numerical models allow us to predict the long-term geochemical evolution of the near field system by means of reactive-transport codes and the information gathered in underground laboratory experiments and natural analogues. Two different scenarios have been defined to model this near field evolution, according to the pathway used by groundwater to contact the near field: a) through a fracture in the host rock intersecting the deposition hole; and b) through the material used to backfill the deposition tunnel. Moreover, we also modelled the effect of different groundwater compositions reaching the near field, as the up-rise of deep-seated brines and the intrusion of ice-melting derived groundwater. We also modelled the effect of the thermal stage due to the heat generated by spent fuel on the geochemical evolution of the bentonite barrier.

  19. Geochemical factors affecting radionuclide transport through near and far fields at a Low-Level Waste Disposal Site

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, D.I.; Seme, R.J. [Pacific Northwest Lab., Richland, WA (United States); Piepkho, M.G. [Westinghouse Hanford Co., Richland, WA (United States)


    The concentration of low-level waste (LLW) contaminants in groundwater is determined by the amount of contaminant present in the solid waste, rate of release from the waste and surrounding barriers, and a number of geochemical processes including adsorption, desorption, diffusion, precipitation, and dissolution. To accurately predict radionuclide transport through the subsurface, it is essential that the important geochemical processes affecting radionuclide transport be identified and, perhaps more importantly, accurately quantified and described in a mathematically defensible manner.

  20. Use of Geochemical and Geophysical Techniques to Characterize and Prospect for Geothermal Resources and Hydrothermal Ore Deposits

    Institute of Scientific and Technical Information of China (English)

    Robert E. Criss


    Fluid-rock interactions alter the geochemical, isotopic, petrographic and physical character of host rocks, producing a permanent record of hydrothermal activity. Maps of altered rock properties show regular variations that disclose master geologic controls and delineate likely sites for geothermal and mineral resources. In many cases, geochemical and stable isotope data re-veal the origins of thermal fluids, and they can also provide estimates of reservoir temperatures and identify zones of fluid recharge.